fSchema.php

<?php
/**
 * Gets schema information for the selected database
 * 
 * @copyright  Copyright (c) 2007-2012 Will Bond
 * @author     Will Bond [wb] <will@flourishlib.com>
 * @license    http://flourishlib.com/license
 * 
 * @package    Flourish
 * @link       http://flourishlib.com/fSchema
 * 
 * @version    1.0.0b51
 * @changes    1.0.0b51  Fixed handling of getting tables in table creation order when a table references itself, fixed default value detection for the last column in a MySQL table [wb, 2012-01-12]
 * @changes    1.0.0b50  Fixed detection of explicitly named SQLite foreign key constraints [wb, 2011-08-23]
 * @changes    1.0.0b49  Added support for spatial/geometric data types in MySQL and PostgreSQL [wb, 2011-05-26]
 * @changes    1.0.0b48  Fixed a bug with ::getTables() not working on MySQL 4.x, fixed ::getKeys() to always return a reset array [wb, 2011-05-24]
 * @changes    1.0.0b47  Backwards Compatibility Break - ::getTables(), ::getColumnInfo(), ::getDatabases(), ::getKeys() and ::getRelationships() now return database, schema, table and column names in lowercase, added the `$creation_order` parameter to ::getTables(), fixed bugs with getting column and key information from MSSQL, Oracle and SQLite [wb, 2011-05-09]
 * @changes    1.0.0b46  Enhanced SQLite schema detection to cover situations where `UNIQUE` constraints are defined separately from the table and when comments are used in `CREATE TABLE` statements [wb, 2011-02-06]
 * @changes    1.0.0b45  Fixed Oracle auto incrementing detection to work with `INSERT OR UPDATE` triggers, fixed detection of dynamic default date/time/timestamp values for DB2 and Oracle [wb, 2010-12-04]
 * @changes    1.0.0b44  Fixed the list of valid elements for ::getColumnInfo() [wb, 2010-11-28]
 * @changes    1.0.0b43  Added the `comment` element to the information returned by ::getColumnInfo() [wb, 2010-11-28]
 * @changes    1.0.0b42  Fixed a bug with MySQL detecting default `ON DELETE` clauses [wb, 2010-10-19]
 * @changes    1.0.0b41  Fixed handling MySQL table names that require quoting [wb, 2010-08-24]
 * @changes    1.0.0b40  Fixed bugs in the documentation and error message of ::getColumnInfo() about what are valid elements [wb, 2010-07-21]
 * @changes    1.0.0b39  Fixed a regression where key detection SQL was not compatible with PostgreSQL 8.1 [wb, 2010-04-13]
 * @changes    1.0.0b38  Added Oracle support to ::getDatabases() [wb, 2010-04-13]
 * @changes    1.0.0b37  Fixed ::getDatabases() for MSSQL [wb, 2010-04-09]
 * @changes    1.0.0b36  Fixed PostgreSQL to properly report explicit `NULL` default values via ::getColumnInfo() [wb, 2010-03-30]
 * @changes    1.0.0b35  Added `max_length` values for various text and blob data types across all databases [wb, 2010-03-29]
 * @changes    1.0.0b34  Added `min_value` and `max_value` attributes to ::getColumnInfo() to specify the valid range for numeric columns [wb, 2010-03-16]
 * @changes    1.0.0b33  Changed it so that PostgreSQL unique indexes containing functions are ignored since they can't be properly detected at this point [wb, 2010-03-14]
 * @changes    1.0.0b32  Fixed ::getTables() to not include views for MySQL [wb, 2010-03-14]
 * @changes    1.0.0b31  Fixed the creation of the default caching key for ::enableCaching() [wb, 2010-03-02]
 * @changes    1.0.0b30  Fixed the class to work with lower privilege Oracle accounts and added detection of Oracle number columns [wb, 2010-01-25]
 * @changes    1.0.0b29  Added on_delete and on_update elements to one-to-one relationship info retrieved by ::getRelationships() [wb, 2009-12-16]
 * @changes    1.0.0b28  Fixed a bug with detecting some multi-column unique constraints in SQL Server databases [wb, 2009-11-13]
 * @changes    1.0.0b27  Added a parameter to ::enableCaching() to provide a key token that will allow cached values to be shared between multiple databases with the same schema [wb, 2009-10-28]
 * @changes    1.0.0b26  Added the placeholder element to the output of ::getColumnInfo(), added support for PostgreSQL, MSSQL and Oracle "schemas", added support for parsing quoted SQLite identifiers [wb, 2009-10-22]
 * @changes    1.0.0b25  One-to-one relationships utilizing the primary key as a foreign key are now properly detected [wb, 2009-09-22]
 * @changes    1.0.0b24  Fixed MSSQL support to work with ODBC database connections [wb, 2009-09-18]
 * @changes    1.0.0b23  Fixed a bug where one-to-one relationships were being listed as many-to-one [wb, 2009-07-21]
 * @changes    1.0.0b22  PostgreSQL UNIQUE constraints that are created as indexes and not table constraints are now properly detected [wb, 2009-07-08]
 * @changes    1.0.0b21  Added support for the UUID data type in PostgreSQL [wb, 2009-06-18]
 * @changes    1.0.0b20  Add caching of merged info, improved performance of ::getColumnInfo() [wb, 2009-06-15]
 * @changes    1.0.0b19  Fixed a couple of bugs with ::setKeysOverride() [wb, 2009-06-04]
 * @changes    1.0.0b18  Added missing support for MySQL mediumint columns [wb, 2009-05-18]
 * @changes    1.0.0b17  Fixed a bug with ::clearCache() not properly reseting the tables and databases list [wb, 2009-05-13]
 * @changes    1.0.0b16  Backwards Compatibility Break - ::setCacheFile() changed to ::enableCaching() and now requires an fCache object, ::flushInfo() renamed to ::clearCache(), added Oracle support [wb, 2009-05-04]
 * @changes    1.0.0b15  Added support for the three different types of identifier quoting in SQLite [wb, 2009-03-28]
 * @changes    1.0.0b14  Added support for MySQL column definitions containing the COLLATE keyword [wb, 2009-03-28]
 * @changes    1.0.0b13  Fixed a bug with detecting PostgreSQL columns having both a CHECK constraint and a UNIQUE constraint [wb, 2009-02-27]
 * @changes    1.0.0b12  Fixed detection of multi-column primary keys in MySQL [wb, 2009-02-27]
 * @changes    1.0.0b11  Fixed an issue parsing MySQL tables with comments [wb, 2009-02-25]
 * @changes    1.0.0b10  Added the ::getDatabases() method [wb, 2009-02-24]
 * @changes    1.0.0b9   Now detects unsigned and zerofill MySQL data types that do not have a parenthetical part [wb, 2009-02-16]
 * @changes    1.0.0b8   Mapped the MySQL data type `'set'` to `'varchar'`, however valid values are not implemented yet [wb, 2009-02-01]
 * @changes    1.0.0b7   Fixed a bug with detecting MySQL timestamp columns [wb, 2009-01-28]
 * @changes    1.0.0b6   Fixed a bug with detecting MySQL columns that accept `NULL` [wb, 2009-01-19]
 * @changes    1.0.0b5   ::setColumnInfo(): fixed a bug with not grabbing the real database schema first, made general improvements [wb, 2009-01-19]
 * @changes    1.0.0b4   Added support for MySQL binary data types, numeric data type options unsigned and zerofill, and per-column character set definitions [wb, 2009-01-17]
 * @changes    1.0.0b3   Fixed detection of the data type of MySQL timestamp columns, added support for dynamic default date/time values [wb, 2009-01-11]
 * @changes    1.0.0b2   Fixed a bug with detecting multi-column unique keys in MySQL [wb, 2009-01-03]
 * @changes    1.0.0b    The initial implementation [wb, 2007-09-25]
 */
class fSchema
{
	/**
	 * The place to cache to
	 * 
	 * @var fCache
	 */
	private $cache = NULL;
	
	/**
	 * The cache prefix to use for cache entries
	 * 
	 * @var string
	 */
	private $cache_prefix;
	
	/**
	 * The cached column info
	 * 
	 * @var array
	 */
	private $column_info = array();
	
	/**
	 * The column info to override
	 * 
	 * @var array
	 */
	private $column_info_override = array();
	
	/**
	 * A reference to an instance of the fDatabase class
	 * 
	 * @var fDatabase
	 */
	private $database = NULL;
	
	/**
	 * The databases on the current database server
	 * 
	 * @var array
	 */
	private $databases = NULL;
	
	/**
	 * The cached key info
	 * 
	 * @var array
	 */
	private $keys = array();
	
	/**
	 * The key info to override
	 * 
	 * @var array
	 */
	private $keys_override = array();
	
	/**
	 * The merged column info
	 * 
	 * @var array
	 */
	private $merged_column_info = array();
	
	/**
	 * The merged key info
	 * 
	 * @var array
	 */
	private $merged_keys = array();
	
	/**
	 * The relationships in the database
	 * 
	 * @var array
	 */
	private $relationships = array();
	
	/**
	 * The tables in the database
	 * 
	 * @var array
	 */
	private $tables = NULL;
	
	
	/**
	 * Sets the database
	 * 
	 * @param  fDatabase $database  The fDatabase instance
	 * @return fSchema
	 */
	public function __construct($database)
	{
		$this->database = $database;
	}
	
	
	/**
	 * All requests that hit this method should be requests for callbacks
	 * 
	 * @internal
	 * 
	 * @param  string $method  The method to create a callback for
	 * @return callback  The callback for the method requested
	 */
	public function __get($method)
	{
		return array($this, $method);		
	}
	
	
	/**
	 * Checks to see if a column is part of a single-column `UNIQUE` key
	 * 
	 * @param  string $table   The table the column is located in
	 * @param  string $column  The column to check
	 * @return boolean  If the column is part of a single-column unique key
	 */
	private function checkForSingleColumnUniqueKey($table, $column)
	{        
		foreach ($this->merged_keys[$table]['unique'] as $key) {
			if (array($column) == $key) {
				return TRUE;
			}
		}
		if (array($column) == $this->merged_keys[$table]['primary']) {
			return TRUE;
		}
		return FALSE;
	}
	
	
	/**
	 * Clears all of the schema info out of the object and, if set, the fCache object
	 * 
	 * @internal
	 * 
	 * @return void
	 */
	public function clearCache()
	{
		$this->column_info        = array();
		$this->databases          = NULL;
		$this->keys               = array();
		$this->merged_column_info = array();
		$this->merged_keys        = array();
		$this->relationships      = array();
		$this->tables             = NULL;
		if ($this->cache) {
			$prefix = $this->makeCachePrefix();
			$this->cache->delete($prefix . 'column_info');
			$this->cache->delete($prefix . 'databases');
			$this->cache->delete($prefix . 'keys');
			$this->cache->delete($prefix . 'merged_column_info');
			$this->cache->delete($prefix . 'merged_keys');
			$this->cache->delete($prefix . 'relationships');
			$this->cache->delete($prefix . 'tables');
		}
	}
	
	
	/**
	 * Returns an ordered array of table names, in a valid table creation order
	 * 
	 * @param string  $filter_table  The only return this table and tables that rely on it
	 * @return array  An array of table names
	 */
	private function determineTableCreationOrder($filter_table=NULL)
	{
		$found          = array();
		$ignored_found  = array();
		
		$current_tables = $this->getTables();
		// Prevent an infinite loop
		$last_tables    = array();
		while ($current_tables && $current_tables != $last_tables) {
			$remaining_tables = array();
			foreach ($current_tables as $table) {
				$foreign_keys = $this->getKeys($table, 'foreign');
				if (!$foreign_keys) {
					if ($filter_table !== NULL) {
						if ($table == $filter_table) {
							$found[] = $table;
						} else {
							$ignored_found[] = $table;
						}
					} else {
						$found[] = $table;
					}
					
				} else {
					$all_dependencies_met = TRUE;
					$found_dependencies   = 0;
					foreach ($foreign_keys as $foreign_key) {
						if ($table != $foreign_key['foreign_table'] && !in_array($foreign_key['foreign_table'], $found) && !in_array($foreign_key['foreign_table'], $ignored_found)) {
							$all_dependencies_met = FALSE;
							break;
						} elseif (in_array($foreign_key['foreign_table'], $found)) {
							$found_dependencies++;
						}
					}
					if ($all_dependencies_met) {
						if ($filter_table !== NULL) {
							if ($found_dependencies || $table == $filter_table) {
								$found[] = $table;
							} else {
								$ignored_found[] = $table;
							}
						} else {
							$found[] = $table;
						}
						
					} else {
						$remaining_tables[] = $table;
					}
				}
			}
			$last_tables    = $current_tables;
			$current_tables = $remaining_tables;
		}
		
		return $found;
	}
	
	
	/**
	 * Sets the schema to be cached to the fCache object specified
	 * 
	 * @param  fCache $cache      The cache to cache to
	 * @param  string $key_token  Internal use only! (this will be used in the cache key to uniquely identify the cache for this fSchema object) 
	 * @return void
	 */
	public function enableCaching($cache, $key_token=NULL)
	{
		$this->cache = $cache;
		
		if ($key_token !== NULL) {
			$this->cache_prefix = 'fSchema::' . $this->database->getType() . '::' . $key_token . '::';
		}
		$prefix = $this->makeCachePrefix();
		
		$this->column_info        = $this->cache->get($prefix . 'column_info',          array());
		$this->databases          = $this->cache->get($prefix . 'databases',            NULL);
		$this->keys               = $this->cache->get($prefix . 'keys',                 array());
		
		if (!$this->column_info_override && !$this->keys_override) {
			$this->merged_column_info = $this->cache->get($prefix . 'merged_column_info',   array());
			$this->merged_keys        = $this->cache->get($prefix . 'merged_keys',          array());  
			$this->relationships      = $this->cache->get($prefix . 'relationships',        array());
		}
		
		$this->tables             = $this->cache->get($prefix . 'tables',               NULL);   
	}
	
	
	/**
	 * Gets the column info from the database for later access
	 * 
	 * @param  string $table  The table to fetch the column info for
	 * @return void
	 */
	private function fetchColumnInfo($table)
	{
		if (isset($this->column_info[$table])) {
			return;	
		}
		
		switch ($this->database->getType()) {
			case 'db2':
				$column_info = $this->fetchDB2ColumnInfo($table);
				break;
			
			case 'mssql':
				$column_info = $this->fetchMSSQLColumnInfo($table);
				break;
			
			case 'mysql':
				$column_info = $this->fetchMySQLColumnInfo($table);
				break;
				
			case 'oracle':
				$column_info = $this->fetchOracleColumnInfo($table);
				break;
			
			case 'postgresql':
				$column_info = $this->fetchPostgreSQLColumnInfo($table);
				break;
				
			case 'sqlite':
				$column_info = $this->fetchSQLiteColumnInfo($table);
				break;
		}
			
		if (!$column_info) {
			return;	
		}
			
		$this->column_info[$table] = $column_info;
		if ($this->cache) {
			$this->cache->set($this->makeCachePrefix() . 'column_info', $this->column_info);	
		}
	}
	
	
	/**
	 * Gets the column info from a DB2 database
	 * 
	 * @param  string $table  The table to fetch the column info for
	 * @return array  The column info for the table specified - see ::getColumnInfo() for details
	 */
	private function fetchDB2ColumnInfo($table)
	{
		$column_info = array();
		
		$schema = strtolower($this->database->getUsername());
		if (strpos($table, '.') !== FALSE) {
			list ($schema, $table) = explode('.', $table);
		}
		
		$data_type_mapping = array(
			'smallint'          => 'integer',
			'integer'           => 'integer',
			'bigint'            => 'integer',
			'timestamp'         => 'timestamp',
			'date'              => 'date',
			'time'              => 'time',
			'varchar'           => 'varchar',
			'long varchar'      => 'varchar',
			'vargraphic'        => 'varchar',
			'long vargraphic'   => 'varchar',
			'character'         => 'char',
			'graphic'           => 'char',
			'real'              => 'float',
			'decimal'           => 'float',
			'numeric'           => 'float',
			'blob'              => 'blob',
			'clob'              => 'text',
			'dbclob'            => 'text'
		);
		
		$max_min_values = array(
			'smallint'   => array('min' => new fNumber(-32768),                  'max' => new fNumber(32767)),
			'integer'    => array('min' => new fNumber(-2147483648),             'max' => new fNumber(2147483647)),
			'bigint'     => array('min' => new fNumber('-9223372036854775808'),  'max' => new fNumber('9223372036854775807'))
		);
		
		// Get the column info
		$sql = "SELECT
					LOWER(C.COLNAME) AS \"COLUMN\",
					C.TYPENAME AS TYPE,
					C.NULLS AS NULLABLE,
					C.DEFAULT,
					C.LENGTH AS MAX_LENGTH,
					C.SCALE,
					CASE WHEN C.IDENTITY = 'Y' AND (C.GENERATED = 'D' OR C.GENERATED = 'A') THEN '1' ELSE '0' END AS AUTO_INCREMENT,
					CH.TEXT AS \"CONSTRAINT\",
					C.REMARKS AS \"COMMENT\"
				FROM
					SYSCAT.COLUMNS AS C LEFT JOIN
					SYSCAT.COLCHECKS AS CC ON
						C.TABSCHEMA = CC.TABSCHEMA AND
						C.TABNAME = CC.TABNAME AND
						C.COLNAME = CC.COLNAME AND
						CC.USAGE = 'R' LEFT JOIN
					SYSCAT.CHECKS AS CH ON
						C.TABSCHEMA = CH.TABSCHEMA AND
						C.TABNAME = CH.TABNAME AND
						CH.TYPE = 'C' AND
						CH.CONSTNAME = CC.CONSTNAME
				WHERE
					LOWER(C.TABSCHEMA) = %s AND
					LOWER(C.TABNAME) = %s
				ORDER BY
					C.COLNO ASC";
		
		$result = $this->database->query($sql, strtolower($schema), strtolower($table));
		
		foreach ($result as $row) {
			
			$info = array();
			
			foreach ($data_type_mapping as $data_type => $mapped_data_type) {
				if (stripos($row['type'], $data_type) === 0) {
					if (isset($max_min_values[$data_type])) {
						$info['min_value'] = $max_min_values[$data_type]['min'];
						$info['max_value'] = $max_min_values[$data_type]['max'];
					}
					$info['type'] = $mapped_data_type;
					break;
				}
			}
			
			// Handle decimal places and min/max for numeric/decimals
			if (in_array(strtolower($row['type']), array('decimal', 'numeric'))) {
				$info['decimal_places'] = $row['scale'];
				$before_digits = str_pad('', $row['max_length'] - $row['scale'], '9');
				$after_digits  = str_pad('', $row['scale'], '9');
				$max_min       = $before_digits . ($after_digits ? '.' : '') . $after_digits;
				$info['min_value'] = new fNumber('-' . $max_min);
				$info['max_value'] = new fNumber($max_min);
			}
			
			if (!isset($info['type'])) {
				$info['type'] = $row['type'];
			}
			
			// Handle the special data for varchar columns
			if (in_array($info['type'], array('char', 'varchar', 'text', 'blob'))) {
				$info['max_length'] = $row['max_length'];
			}
			
			// The generally accepted practice for boolean on DB2 is a CHAR(1) with a CHECK constraint
			if ($info['type'] == 'char' && $info['max_length'] == 1 && !empty($row['constraint'])) {
				if (is_resource($row['constraint'])) {
					$row['constraint'] = stream_get_contents($row['constraint']);
				}
				if (preg_match('/^\s*"?' . preg_quote($row['column'], '/') . '"?\s+in\s+\(\s*(\'0\',\s*\'1\'|\'1\',\s*\'0\')\s*\)\s*$/i', $row['constraint'])) {
					$info['type'] = 'boolean';
					$info['max_length'] = NULL;
				}
			}
			
			// If the column has a constraint, look for valid values
			if (in_array($info['type'], array('char', 'varchar')) && !empty($row['constraint'])) {
				if (preg_match('/^\s*"?' . preg_quote($row['column'], '/') . '"?\s+in\s+\((.*?)\)\s*$/i', $row['constraint'], $match)) {
					if (preg_match_all("/(?<!')'((''|[^']+)*)'/", $match[1], $matches, PREG_PATTERN_ORDER)) {
						$info['valid_values'] = str_replace("''", "'", $matches[1]);
					}			
				}
			}
			
			// Handle auto increment
			if ($row['auto_increment']) {
				$info['auto_increment'] = TRUE;
			}
			
			// Handle default values
			if ($row['default'] !== NULL) {
				if ($row['default'] == 'NULL') {
					$info['default'] = NULL;
				} elseif (in_array($info['type'], array('timestamp', 'date', 'time')) && $row['default'][0] != "'") {
					$info['default'] = str_replace(' ', '_', $row['default']);
				} elseif (in_array($info['type'], array('char', 'varchar', 'text', 'timestamp', 'date', 'time')) ) {
					$info['default'] = substr($row['default'], 1, -1);
				} elseif ($info['type'] == 'boolean') {
					$info['default'] = (boolean) substr($row['default'], 1, -1);
				} else {
					$info['default'] = $row['default'];
				}
			}
			
			// Handle not null
			$info['not_null'] = ($row['nullable'] == 'N') ? TRUE : FALSE;
			
			$info['comment'] = $row['comment'];
			
			$column_info[$row['column']] = $info;
		}
		
		return $column_info;
	}
	
	
	/**
	 * Fetches the key info for a DB2 database
	 * 
	 * @return array  The keys arrays for every table in the database - see ::getKeys() for details
	 */
	private function fetchDB2Keys()
	{
		$keys = array();
		
		$default_schema = strtolower($this->database->getUsername());
		
		$tables = $this->getTables();
		foreach ($tables as $table) {
			$keys[$table] = array();
			$keys[$table]['primary'] = array();
			$keys[$table]['unique']  = array();
			$keys[$table]['foreign'] = array();
		}
		
		$params  = array();
		
		$sql  = "(SELECT
					LOWER(RTRIM(R.TABSCHEMA)) AS \"SCHEMA\",
					LOWER(R.TABNAME) AS \"TABLE\",
					R.CONSTNAME AS CONSTRAINT_NAME,
					'foreign' AS \"TYPE\",
					LOWER(K.COLNAME) AS \"COLUMN\",
					LOWER(RTRIM(R.REFTABSCHEMA)) AS FOREIGN_SCHEMA,
					LOWER(R.REFTABNAME) AS FOREIGN_TABLE,
					LOWER(FK.COLNAME) AS FOREIGN_COLUMN,
					CASE R.DELETERULE WHEN 'C' THEN 'cascade' WHEN 'A' THEN 'no_action' WHEN 'R' THEN 'restrict' ELSE 'set_null' END AS ON_DELETE,
					CASE R.UPDATERULE WHEN 'A' THEN 'no_action' WHEN 'R' THEN 'restrict' END AS ON_UPDATE,
					K.COLSEQ
				FROM
					SYSCAT.REFERENCES AS R INNER JOIN 
					SYSCAT.KEYCOLUSE AS K ON
						R.CONSTNAME = K.CONSTNAME AND
						R.TABSCHEMA = K.TABSCHEMA AND
						R.TABNAME = K.TABNAME INNER JOIN
					SYSCAT.KEYCOLUSE AS FK ON
						R.REFKEYNAME = FK.CONSTNAME AND
						R.REFTABSCHEMA = FK.TABSCHEMA AND
						R.REFTABNAME = FK.TABNAME
				WHERE ";
		
		$conditions = array();
		foreach ($tables as $table) {
			if (strpos($table, '.') === FALSE) {
				$table = $default_schema . '.' . $table;
			}	
			list ($schema, $table) = explode('.', strtolower($table));
			$conditions[] = "LOWER(R.TABSCHEMA) = %s AND LOWER(R.TABNAME) = %s";
			$params[] = $schema;
			$params[] = $table;
		}
		$sql .= '((' . join(') OR( ', $conditions) . '))';
		 
		$sql .= "
				) UNION (
				SELECT
					LOWER(RTRIM(I.TABSCHEMA)) AS \"SCHEMA\",
					LOWER(I.TABNAME) AS \"TABLE\",
					LOWER(I.INDNAME) AS CONSTRAINT_NAME,
					CASE I.UNIQUERULE WHEN 'U' THEN 'unique' ELSE 'primary' END AS \"TYPE\",
					LOWER(C.COLNAME) AS \"COLUMN\",
					NULL AS FOREIGN_SCHEMA,
					NULL AS FOREIGN_TABLE,
					NULL AS FOREIGN_COLUMN,
					NULL AS ON_DELETE,
					NULL AS ON_UPDATE,
					C.COLSEQ
				FROM
					SYSCAT.INDEXES AS I INNER JOIN
					SYSCAT.INDEXCOLUSE AS C ON I.INDSCHEMA = C.INDSCHEMA AND I.INDNAME = C.INDNAME
				WHERE
					I.UNIQUERULE IN ('U', 'P') AND
					";
		
		$conditions = array();
		foreach ($tables as $table) {
			if (strpos($table, '.') === FALSE) {
				$table = $default_schema . '.' . $table;
			}	
			list ($schema, $table) = explode('.', strtolower($table));
			$conditions[] = "LOWER(I.TABSCHEMA) = %s AND LOWER(I.TABNAME) = %s";
			$params[] = $schema;
			$params[] = $table;
		}
		$sql .= '((' . join(') OR( ', $conditions) . '))';
		
		$sql .= "
				 )
				 ORDER BY 4, 1, 2, 3, 11";
		
		$result = $this->database->query($sql, $params);
		
		$last_name  = '';
		$last_table = '';
		$last_type  = '';
		foreach ($result as $row) {
			
			if ($row['constraint_name'] != $last_name) {
				
				if ($last_name) {
					if ($last_type == 'foreign' || $last_type == 'unique') {
						$keys[$last_table][$last_type][] = $temp;
					} else {
						$keys[$last_table][$last_type] = $temp;
					}
				}
				
				$temp = array();
				if ($row['type'] == 'foreign') {
					
					$temp['column']         = $row['column'];
					$temp['foreign_table']  = $row['foreign_table'];
					if ($row['foreign_schema'] != $default_schema) {
						$temp['foreign_table'] = $row['foreign_schema'] . '.' . $temp['foreign_table'];
					}
					$temp['foreign_column'] = $row['foreign_column'];
					$temp['on_delete']      = 'no_action';
					$temp['on_update']      = 'no_action';
					
					if (!empty($row['on_delete'])) {
						$temp['on_delete'] = $row['on_delete'];
					}
					if (!empty($row['on_update'])) {
						$temp['on_update'] = $row['on_update'];
					}
					
				} else {
					$temp[] = $row['column'];
				}
				
				$last_table = $row['table'];
				if ($row['schema'] != $default_schema) {
					$last_table = $row['schema'] . '.' . $last_table;
				}
				$last_name  = $row['constraint_name'];
				$last_type  = $row['type'];
				
			} else {
				$temp[] = $row['column'];
			}
		}
		
		if (isset($temp)) {
			if ($last_type == 'foreign' || $last_type == 'unique') {
				$keys[$last_table][$last_type][] = $temp;
			} else {
				$keys[$last_table][$last_type] = $temp;
			}
		}
		
		return $keys;
	}
	
	
	/**
	 * Gets the `PRIMARY KEY`, `FOREIGN KEY` and `UNIQUE` key constraints from the database
	 * 
	 * @return void
	 */
	private function fetchKeys()
	{
		if ($this->keys) {
			return;	
		}
		
		switch ($this->database->getType()) {
			case 'db2':
				$keys = $this->fetchDB2Keys();
				break;
			
			case 'mssql':
				$keys = $this->fetchMSSQLKeys();
				break;
				
			case 'mysql':
				$keys = $this->fetchMySQLKeys();
				break;
				
			case 'oracle':
				$keys = $this->fetchOracleKeys();
				break;
			
			case 'postgresql':
				$keys = $this->fetchPostgreSQLKeys();
				break;
			
			case 'sqlite':
				$keys = $this->fetchSQLiteKeys();
				break;
		}
		
		$this->keys = $keys;
		if ($this->cache) {
			$this->cache->set($this->makeCachePrefix() . 'keys', $this->keys);	
		}
	}
	
	
	/**
	 * Gets the column info from a MSSQL database
	 * 
	 * @param  string $table  The table to fetch the column info for
	 * @return array  The column info for the table specified - see ::getColumnInfo() for details
	 */
	private function fetchMSSQLColumnInfo($table)
	{
		$column_info = array();
		
		$schema = 'dbo';
		if (strpos($table, '.') !== FALSE) {
			list ($schema, $table) = explode('.', $table);
		}
		
		$data_type_mapping = array(
			'bit'               => 'boolean',
			'tinyint'           => 'integer',
			'smallint'          => 'integer',
			'int'               => 'integer',
			'bigint'            => 'integer',
			'timestamp'         => 'integer',
			'datetime'          => 'timestamp',
			'smalldatetime'     => 'timestamp',
			'datetime2'         => 'timestamp',
			'date'              => 'date',
			'time'              => 'time',
			'varchar'           => 'varchar',
			'nvarchar'          => 'varchar',
			'uniqueidentifier'  => 'varchar',
			'char'              => 'char',
			'nchar'             => 'char',
			'real'              => 'float',
			'float'             => 'float',
			'money'             => 'float',
			'smallmoney'        => 'float',
			'decimal'           => 'float',
			'numeric'           => 'float',
			'binary'            => 'blob',
			'varbinary'         => 'blob',
			'image'             => 'blob',
			'text'              => 'text',
			'ntext'             => 'text',
			'xml'               => 'text'
		);
		
		$max_min_values = array(
			'tinyint'    => array('min' => new fNumber(0),                       'max' => new fNumber(255)),
			'smallint'   => array('min' => new fNumber(-32768),                  'max' => new fNumber(32767)),
			'int'        => array('min' => new fNumber(-2147483648),             'max' => new fNumber(2147483647)),
			'bigint'     => array('min' => new fNumber('-9223372036854775808'),  'max' => new fNumber('9223372036854775807')),
			'smallmoney' => array('min' => new fNumber('-214748.3648'),          'max' => new fNumber('214748.3647')),
			'money'      => array('min' => new fNumber('-922337203685477.5808'), 'max' => new fNumber('922337203685477.5807'))
		);
		
		// Get the column info
		$sql = "SELECT
					LOWER(c.column_name)       AS 'column',
					c.data_type                AS 'type',
					c.is_nullable              AS nullable,
					c.column_default           AS 'default',
					c.character_maximum_length AS max_length,
					c.numeric_precision        AS precision,
					c.numeric_scale            AS decimal_places,
					CASE
						WHEN
							COLUMNPROPERTY(OBJECT_ID(QUOTENAME(c.table_schema) + '.' + QUOTENAME(c.table_name)), c.column_name, 'IsIdentity') = 1 AND
							OBJECTPROPERTY(OBJECT_ID(QUOTENAME(c.table_schema) + '.' + QUOTENAME(c.table_name)), 'IsMSShipped') = 0
						THEN '1'
						ELSE '0'
					END AS auto_increment,
					cc.check_clause AS 'constraint',
					CAST(ex.value AS VARCHAR(7500)) AS 'comment'
				FROM
					INFORMATION_SCHEMA.COLUMNS AS c LEFT JOIN
					INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE AS ccu ON
						c.column_name = ccu.column_name AND
						c.table_name = ccu.table_name AND
						c.table_catalog = ccu.table_catalog LEFT JOIN
					INFORMATION_SCHEMA.CHECK_CONSTRAINTS AS cc ON
						ccu.constraint_name = cc.constraint_name AND
						ccu.constraint_catalog = cc.constraint_catalog";
		
		if (version_compare($this->database->getVersion(), 9, '<')) {
			$sql .= " LEFT JOIN sysproperties AS ex ON ex.id = OBJECT_ID(QUOTENAME(c.table_schema) + '.' + QUOTENAME(c.table_name)) AND ex.smallid = COLUMNPROPERTY(OBJECT_ID(QUOTENAME(c.table_schema) + '.' + QUOTENAME(c.table_name)), c.column_name, 'ColumnId') AND ex.name = 'MS_Description' AND OBJECTPROPERTY(OBJECT_ID(QUOTENAME(c.table_schema) + '.' + QUOTENAME(c.table_name)), 'IsMsShipped') = 0 ";
		} else {
			$sql .= " LEFT JOIN SYS.EXTENDED_PROPERTIES AS ex ON ex.major_id = OBJECT_ID(QUOTENAME(c.table_schema) + '.' + QUOTENAME(c.table_name)) AND ex.minor_id = COLUMNPROPERTY(OBJECT_ID(QUOTENAME(c.table_schema) + '.' + QUOTENAME(c.table_name)), c.column_name, 'ColumnId') AND ex.name = 'MS_Description' AND OBJECTPROPERTY(OBJECT_ID(QUOTENAME(c.table_schema) + '.' + QUOTENAME(c.table_name)), 'IsMsShipped') = 0 ";
		}
		
		$sql .= "
					WHERE
						LOWER(c.table_name) = %s AND
						LOWER(c.table_schema) = %s AND
						c.table_catalog = DB_NAME()";
		
		$result = $this->database->query($sql, strtolower($table), strtolower($schema));
		
		foreach ($result as $row) {
			
			$info = array();
			
			foreach ($data_type_mapping as $data_type => $mapped_data_type) {
				if (stripos($row['type'], $data_type) === 0) {
					if (isset($max_min_values[$data_type])) {
						$info['min_value'] = $max_min_values[$data_type]['min'];
						$info['max_value'] = $max_min_values[$data_type]['max'];
					}
					$info['type'] = $mapped_data_type;
					break;
				}
			}
			
			// Handle decimal places and min/max for numeric/decimals
			if (in_array(strtolower($row['type']), array('decimal', 'numeric'))) {
				$info['decimal_places'] = $row['decimal_places'];
				$before_digits = str_pad('', $row['precision'] - $row['decimal_places'], '9');
				$after_digits  = str_pad('', $row['decimal_places'], '9');
				$max_min       = $before_digits . ($after_digits ? '.' : '') . $after_digits;
				$info['min_value'] = new fNumber('-' . $max_min);
				$info['max_value'] = new fNumber($max_min);
			}
			
			if (!isset($info['type'])) {
				$info['type'] = $row['type'];
			}
			
			// Handle decimal places for money/smallmoney
			if (in_array($row['type'], array('money', 'smallmoney'))) {
				$info['decimal_places'] = 2;
			}
			
			// Handle the special data for varchar columns
			if (in_array($info['type'], array('char', 'varchar', 'text', 'blob'))) {
				if ($row['type'] == 'uniqueidentifier') {
					$row['max_length'] = 32;
				} elseif ($row['max_length'] == -1) {
					$row['max_length'] = $row['type'] == 'nvarchar' ? 1073741823 : 2147483647;
				}
				$info['max_length'] = $row['max_length'];
			}
			
			// If the column has a constraint, look for valid values
			if (in_array($info['type'], array('char', 'varchar')) && !empty($row['constraint'])) {
				if (preg_match('#^\(((?:(?: OR )?\[[^\]]+\]\s*=\s*\'(?:\'\'|[^\']+)*\')+)\)$#D', $row['constraint'], $matches)) {
					$valid_values = explode(' OR ', $matches[1]);
					foreach ($valid_values as $key => $value) {
						$value = preg_replace('#^\s*\[' . preg_quote($row['column'], '#') . '\]\s*=\s*\'(.*)\'\s*$#', '\1', $value);
						$valid_values[$key] = str_replace("''", "'", $value);
					}
					// SQL Server turns CHECK constraint values into a reversed list, so we fix it here
					$info['valid_values'] = array_reverse($valid_values);
				}
			}
			
			// Handle auto increment
			if ($row['auto_increment']) {
				$info['auto_increment'] = TRUE;
			}
			
			// Handle default values
			if ($row['default'] !== NULL) {
				if ($row['default'] == '(getdate())') {
					$info['default'] = 'CURRENT_TIMESTAMP';
				} elseif (in_array($info['type'], array('char', 'varchar', 'text', 'timestamp')) ) {
					$info['default'] = substr($row['default'], 2, -2);
				} elseif ($info['type'] == 'boolean') {
					$info['default'] = (boolean) substr($row['default'], 2, -2);
				} elseif (in_array($info['type'], array('integer', 'float')) ) {
					$info['default'] = str_replace(array('(', ')'), '', $row['default']);
				} else {
					$info['default'] = pack('H*', substr($row['default'], 3, -1));
				}
			}
			
			// Handle not null
			$info['not_null'] = ($row['nullable'] == 'NO') ? TRUE : FALSE;
			
			$info['comment'] = $row['comment'];
			
			$column_info[$row['column']] = $info;
		}
		
		return $column_info;
	}
	
	
	/**
	 * Fetches the key info for an MSSQL database
	 * 
	 * @return array  The key info arrays for every table in the database - see ::getKeys() for details
	 */
	private function fetchMSSQLKeys()
	{
		$keys = array();
		
		$tables   = $this->getTables();
		foreach ($tables as $table) {
			$keys[$table] = array();
			$keys[$table]['primary'] = array();
			$keys[$table]['unique']  = array();
			$keys[$table]['foreign'] = array();
		}
		
		$sql  = "SELECT
					LOWER(c.table_schema) AS \"schema\",
					LOWER(c.table_name) AS \"table\",
					kcu.constraint_name AS constraint_name,
					CASE c.constraint_type
						WHEN 'PRIMARY KEY' THEN 'primary'
						WHEN 'FOREIGN KEY' THEN 'foreign'
						WHEN 'UNIQUE' THEN 'unique'
					END AS 'type',
					LOWER(kcu.column_name) AS 'column',
					LOWER(ccu.table_schema) AS foreign_schema,
					LOWER(ccu.table_name) AS foreign_table,
					LOWER(ccu.column_name) AS foreign_column,
					REPLACE(LOWER(rc.delete_rule), ' ', '_') AS on_delete,
					REPLACE(LOWER(rc.update_rule), ' ', '_') AS on_update
				FROM
					INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS c INNER JOIN
					INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS kcu ON
						c.table_name = kcu.table_name AND
						c.constraint_name = kcu.constraint_name LEFT JOIN
					INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS AS rc ON
						c.constraint_name = rc.constraint_name LEFT JOIN
					INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE AS ccu ON
						ccu.constraint_name = rc.unique_constraint_name
				WHERE
					c.constraint_catalog = DB_NAME() AND
					c.table_name != 'sysdiagrams'
				ORDER BY
					LOWER(c.table_schema),
					LOWER(c.table_name),
					c.constraint_type,
					LOWER(kcu.constraint_name),
					kcu.ordinal_position,
					LOWER(kcu.column_name)";
		
		$result = $this->database->query($sql);
		
		$last_name  = '';
		$last_table = '';
		$last_type  = '';
		foreach ($result as $row) {
			
			if ($row['constraint_name'] != $last_name) {
				
				if ($last_name) {
					if ($last_type == 'foreign' || $last_type == 'unique') {
						if (!isset($keys[$last_table][$last_type])) {
							$keys[$last_table][$last_type] = array();		
						}
						$keys[$last_table][$last_type][] = $temp;
					} else {
						$keys[$last_table][$last_type] = $temp;
					}
				}
				
				$temp = array();
				if ($row['type'] == 'foreign') {
					
					$temp['column']         = $row['column'];
					$temp['foreign_table']  = $row['foreign_table'];
					if ($row['foreign_schema'] != 'dbo') {
						 $temp['foreign_table'] = $row['foreign_schema'] . '.' . $temp['foreign_table'];	
					}
					$temp['foreign_column'] = $row['foreign_column'];
					$temp['on_delete']      = 'no_action';
					$temp['on_update']      = 'no_action';
					if (!empty($row['on_delete'])) {
						$temp['on_delete'] = $row['on_delete'];
					}
					if (!empty($row['on_update'])) {
						$temp['on_update'] = $row['on_update'];
					}
					
				} else {
					$temp[] = $row['column'];
				}
				
				$last_table = $row['table'];
				if ($row['schema'] != 'dbo') {
					$last_table = $row['schema'] . '.' . $last_table;	
				}
				$last_name  = $row['constraint_name'];
				$last_type  = $row['type'];
				
			} else {
				$temp[] = $row['column'];
			}
		}
		
		if (isset($temp)) {
			if ($last_type == 'foreign' || $last_type == 'unique') {
				if (!isset($keys[$last_table][$last_type])) {
					$keys[$last_table][$last_type] = array();		
				}
				$keys[$last_table][$last_type][] = $temp;
			} else {
				$keys[$last_table][$last_type] = $temp;
			}
		}
		
		return $keys;
	}
	
	
	/**
	 * Gets the column info from a MySQL database
	 * 
	 * @param  string $table  The table to fetch the column info for
	 * @return array  The column info for the table specified - see ::getColumnInfo() for details
	 */
	private function fetchMySQLColumnInfo($table)
	{
		$data_type_mapping = array(
			'tinyint'			=> 'integer',
			'smallint'			=> 'integer',
			'mediumint'         => 'integer',
			'int'				=> 'integer',
			'bigint'			=> 'integer',
			'datetime'			=> 'timestamp',
			'timestamp'			=> 'timestamp',
			'date'				=> 'date',
			'time'				=> 'time',
			'enum'				=> 'varchar',
			'set'               => 'varchar',
			'varchar'			=> 'varchar',
			'char'				=> 'char',
			'float'				=> 'float',
			'double'			=> 'float',
			'decimal'			=> 'float',
			'binary'            => 'blob',
			'varbinary'         => 'blob',
			'tinyblob'			=> 'blob',
			'blob'				=> 'blob',
			'mediumblob'		=> 'blob',
			'longblob'			=> 'blob',
			'tinytext'			=> 'text',
			'text'				=> 'text',
			'mediumtext'		=> 'text',
			'longtext'			=> 'text',
			'geometry'          => 'blob',
			'point'             => 'blob',
			'linestring'        => 'blob',
			'polygon'           => 'blob'
		);
		
		$max_min_values = array(
			'tinyint'             => array('min' => new fNumber(-128),                    'max' => new fNumber(127)),
			'unsigned tinyint'    => array('min' => new fNumber(0),                       'max' => new fNumber(255)),
			'smallint'            => array('min' => new fNumber(-32768),                  'max' => new fNumber(32767)),
			'unsigned smallint'   => array('min' => new fNumber(0),                       'max' => new fNumber(65535)),
			'mediumint'           => array('min' => new fNumber(-8388608),                'max' => new fNumber(8388607)),
			'unsigned mediumint'  => array('min' => new fNumber(0),                       'max' => new fNumber(16777215)),
			'int'                 => array('min' => new fNumber(-2147483648),             'max' => new fNumber(2147483647)),
			'unsigned int'        => array('min' => new fNumber(0),                       'max' => new fNumber('4294967295')),
			'bigint'              => array('min' => new fNumber('-9223372036854775808'),  'max' => new fNumber('9223372036854775807')),
			'unsigned bigint'     => array('min' => new fNumber(0),                       'max' => new fNumber('18446744073709551615'))
		);
		
		$column_info = array();
		
		$result     = $this->database->query('SHOW CREATE TABLE %r', $table);
		
		try {
			$row        = $result->fetchRow();
			$create_sql = $row['Create Table'];
		} catch (fNoRowsException $e) {
			return array();
		}
		
		preg_match_all('#(?<=,|\()\s+(?:"|\`)(\w+)(?:"|\`)\s+(?:([a-z]+)(?:\(([^)]+)\))?( unsigned)?(?: zerofill)?)(?: character set [^ ]+)?(?: collate [^ ]+)?(?: NULL)?( NOT NULL)?(?: DEFAULT ((?:[^, \'\n]*|\'(?:\'\'|[^\']+)*\')))?( auto_increment)?( COMMENT \'(?:\'\'|[^\']+)*\')?( ON UPDATE CURRENT_TIMESTAMP)?\s*(?:,|\s*(?=\)))#mi', $create_sql, $matches, PREG_SET_ORDER);
		
		foreach ($matches as $match) {
			
			$info = array();
			
			foreach ($data_type_mapping as $data_type => $mapped_data_type) {
				if (stripos($match[2], $data_type) === 0) {
					if ($match[2] == 'tinyint' && $match[3] == 1) {
						$mapped_data_type = 'boolean';
					
					} elseif (preg_match('#((?:unsigned )?(?:tiny|small|medium|big)?int)#', (isset($match[4]) ? $match[4] . ' ' : '') . $data_type, $int_match)) {
						if (isset($max_min_values[$int_match[1]])) {
							$info['min_value'] = $max_min_values[$int_match[1]]['min'];
							$info['max_value'] = $max_min_values[$int_match[1]]['max'];	
						}
					}
					
					$info['type'] = $mapped_data_type;
					break;
				}
			}
			if (!isset($info['type'])) {
				$info['type'] = preg_replace('#^([a-z ]+).*$#iD', '\1', $match[2]);
			}
			
			switch ($match[2]) {
				case 'tinyblob':
				case 'tinytext':
					$info['max_length'] = 255;
					break;
				
				case 'blob':
				case 'text':
					$info['max_length'] = 65535;
					break;
				
				case 'mediumblob':
				case 'mediumtext':
					$info['max_length'] = 16777215;
					break;
				
				case 'longblob':
				case 'longtext':
					$info['max_length'] = 4294967295;
					break;
			}
		
			if (stripos($match[2], 'enum') === 0) {
				$info['valid_values'] = preg_replace("/^'|'\$/D", '', explode(",", $match[3]));
				$match[3] = 0;
				foreach ($info['valid_values'] as $valid_value) {
					if (strlen(utf8_decode($valid_value)) > $match[3]) {
						$match[3] = strlen(utf8_decode($valid_value));
					}
				}
			}
			
			// The set data type is currently only supported as a varchar
			// with a max length of all valid values concatenated by ,s
			if (stripos($match[2], 'set') === 0) {
				$values = preg_replace("/^'|'\$/D", '', explode(",", $match[3]));
				$match[3] = strlen(join(',', $values));
			}
			
			// Type specific information
			if (in_array($info['type'], array('char', 'varchar'))) {
				$info['max_length'] = $match[3];
			}
			
			// Grab the number of decimal places
			if (stripos($match[2], 'decimal') === 0) {
				if (preg_match('#^\s*(\d+)\s*,\s*(\d+)\s*$#D', $match[3], $data_type_info)) {
					$info['decimal_places'] = $data_type_info[2];
					$before_digits = str_pad('', $data_type_info[1] - $info['decimal_places'], '9');
					$after_digits  = str_pad('', $info['decimal_places'], '9');
					$max_min       = $before_digits . ($after_digits ? '.' : '') . $after_digits;
					$info['min_value'] = new fNumber('-' . $max_min);
					$info['max_value'] = new fNumber($max_min);
				}
			}
			
			// Not null
			$info['not_null'] = (!empty($match[5])) ? TRUE : FALSE;
		
			// Default values
			if (!empty($match[6]) && $match[6] != 'NULL') {
				$info['default'] = preg_replace("/^'|'\$/D", '', $match[6]);
			}
			
			if ($info['type'] == 'boolean' && isset($info['default'])) {
				$info['default'] = (boolean) $info['default'];
			}
		
			// Auto increment fields
			if (!empty($match[7])) {
				$info['auto_increment'] = TRUE;
			}
			
			// Column comments
			if (!empty($match[8])) {
				$info['comment'] = str_replace("''", "'", substr($match[8], 10, -1));
			}
		
			$column_info[strtolower($match[1])] = $info;
		}
		
		return $column_info;
	}
	
	
	/**
	 * Fetches the keys for a MySQL database
	 * 
	 * @return array  The keys arrays for every table in the database - see ::getKeys() for details
	 */
	private function fetchMySQLKeys()
	{
		$tables   = $this->getTables();
		$keys = array();
		
		foreach ($tables as $table) {
			
			$keys[$table] = array();
			$keys[$table]['primary'] = array();
			$keys[$table]['foreign'] = array();
			$keys[$table]['unique']  = array();
			
			$result = $this->database->query('SHOW CREATE TABLE %r', $table);
			$row    = $result->fetchRow();
			
			// Primary keys
			preg_match_all('/PRIMARY KEY\s+\("(.*?)"\),?\n/U', $row['Create Table'], $matches, PREG_SET_ORDER);
			if (!empty($matches)) {
				$keys[$table]['primary'] = explode('","', strtolower($matches[0][1]));
			}
			
			// Unique keys
			preg_match_all('/UNIQUE KEY\s+"([^"]+)"\s+\("(.*?)"\),?\n/U', $row['Create Table'], $matches, PREG_SET_ORDER);
			foreach ($matches as $match) {
				$keys[$table]['unique'][] = explode('","', strtolower($match[2]));
			}
			
			// Foreign keys
			preg_match_all('#FOREIGN KEY \("([^"]+)"\) REFERENCES "([^"]+)" \("([^"]+)"\)(?:\sON\sDELETE\s(SET\sNULL|SET\sDEFAULT|CASCADE|NO\sACTION|RESTRICT))?(?:\sON\sUPDATE\s(SET\sNULL|SET\sDEFAULT|CASCADE|NO\sACTION|RESTRICT))?#', $row['Create Table'], $matches, PREG_SET_ORDER);
			foreach ($matches as $match) {
				$temp = array(
					'column'         => strtolower($match[1]),
					'foreign_table'  => strtolower($match[2]),
					'foreign_column' => strtolower($match[3]),
					'on_delete'      => 'no_action',
					'on_update'      => 'no_action'
				);
				if (!empty($match[4])) {
					$temp['on_delete'] = strtolower(str_replace(' ', '_', $match[4]));
				}
				if (!empty($match[5])) {
					$temp['on_update'] = strtolower(str_replace(' ', '_', $match[5]));
				}
				$keys[$table]['foreign'][] = $temp;
			}
		}
		
		return $keys;
	}
	
	
	/**
	 * Gets the column info from an Oracle database
	 * 
	 * @param  string $table  The table to fetch the column info for
	 * @return array  The column info for the table specified - see ::getColumnInfo() for details
	 */
	private function fetchOracleColumnInfo($table)
	{
		$table = strtolower($table);
		
		$schema = strtolower($this->database->getUsername());
		if (strpos($table, '.') !== FALSE) {
			list ($schema, $table) = explode('.', $table);
		}
		
		$column_info = array();
		
		$data_type_mapping = array(
			'boolean'			=> 'boolean',
			'number'            => 'integer',
			'integer'			=> 'integer',
			'timestamp'			=> 'timestamp',
			'date'				=> 'date',
			'varchar2'          => 'varchar',
			'nvarchar2'			=> 'varchar',
			'char'              => 'char',
			'nchar'             => 'char',
			'float'				=> 'float',
			'binary_float'      => 'float',
			'binary_double'     => 'float',
			'blob'				=> 'blob',
			'bfile'             => 'varchar',
			'clob'				=> 'text',
			'nclob'             => 'text'
		);
		
		$sql = "SELECT
					LOWER(ATC.COLUMN_NAME) COLUMN_NAME,
					CASE
						WHEN
							ATC.DATA_TYPE = 'NUMBER' AND
							ATC.DATA_PRECISION IS NULL AND
							ATC.DATA_SCALE = 0
						THEN
							'integer'
						WHEN
							ATC.DATA_TYPE = 'NUMBER' AND
							ATC.DATA_PRECISION = 1 AND
							ATC.DATA_SCALE = 0
						THEN
							'boolean'
						WHEN
							ATC.DATA_TYPE = 'NUMBER' AND
							ATC.DATA_PRECISION IS NOT NULL AND
							ATC.DATA_SCALE != 0 AND
							ATC.DATA_SCALE IS NOT NULL
						THEN
							'float'
						ELSE
							LOWER(ATC.DATA_TYPE)
						END DATA_TYPE,
					CASE
						WHEN
							ATC.CHAR_LENGTH <> 0
						THEN
							ATC.CHAR_LENGTH
						WHEN
							ATC.DATA_TYPE = 'NUMBER' AND
							ATC.DATA_PRECISION != 1 AND
							ATC.DATA_SCALE != 0	AND
							ATC.DATA_PRECISION IS NOT NULL
						THEN
							ATC.DATA_SCALE
						ELSE
							NULL
						END LENGTH,
					ATC.DATA_PRECISION PRECISION,
					ATC.NULLABLE,
					ATC.DATA_DEFAULT,
					AC.SEARCH_CONDITION CHECK_CONSTRAINT,
					ACCM.COMMENTS
				FROM
					ALL_TAB_COLUMNS ATC LEFT JOIN
					ALL_CONS_COLUMNS ACC ON
						ATC.OWNER = ACC.OWNER AND
						ATC.COLUMN_NAME = ACC.COLUMN_NAME AND
						ATC.TABLE_NAME = ACC.TABLE_NAME AND
						ACC.POSITION IS NULL LEFT JOIN
					ALL_CONSTRAINTS AC ON
						AC.OWNER = ACC.OWNER AND
						AC.CONSTRAINT_NAME = ACC.CONSTRAINT_NAME AND
						AC.CONSTRAINT_TYPE = 'C' AND
						AC.STATUS = 'ENABLED' LEFT JOIN
					ALL_COL_COMMENTS ACCM ON
						ATC.OWNER = ACCM.OWNER AND
						ATC.COLUMN_NAME = ACCM.COLUMN_NAME AND
						ATC.TABLE_NAME = ACCM.TABLE_NAME
				WHERE
					LOWER(ATC.TABLE_NAME) = %s AND
					LOWER(ATC.OWNER) = %s
				ORDER BY
					ATC.TABLE_NAME ASC,
					ATC.COLUMN_ID ASC";
		
		$result = $this->database->query($sql, $table, $schema);
		
		foreach ($result as $row) {
			
			$column = $row['column_name'];
			
			// Since Oracle stores check constraints in LONG columns, it is
			// not possible to check or modify the constraints in SQL which
			// ends up causing multiple rows with duplicate data except for
			// the check constraint
			$duplicate = FALSE;
			
			if (isset($column_info[$column])) {
				$info = $column_info[$column];
				$duplicate = TRUE;
			} else {
				$info = array();
			}
			
			if (!$duplicate) {
				// Get the column type
				foreach ($data_type_mapping as $data_type => $mapped_data_type) {
					if (stripos($row['data_type'], $data_type) === 0) {
						$info['type'] = $mapped_data_type;
						break;
					}
				}
				
				if (!isset($info['type'])) {
					$info['type'] = $row['data_type'];
				}
				
				if (in_array($info['type'], array('blob', 'text'))) {
					$info['max_length'] = 4294967295;
				}
				
				if ($row['data_type'] == 'float' && $row['precision']) {
					$row['length'] = (int) $row['length'];
					$before_digits = str_pad('', $row['precision'] - $row['length'], '9');
					$after_digits  = str_pad('', $row['length'], '9');
					$max_min       = $before_digits . ($after_digits ? '.' : '') . $after_digits;
					$info['min_value'] = new fNumber('-' . $max_min);
					$info['max_value'] = new fNumber($max_min);	
				}
				
				// Handle the length of decimal/numeric fields
				if ($info['type'] == 'float' && $row['length']) {
					$info['decimal_places'] = (int) $row['length'];
				}
				
				// Handle the special data for varchar fields
				if (in_array($info['type'], array('char', 'varchar'))) {
					$info['max_length'] = (int) $row['length'];
				}
			}
			
			// Handle check constraints that are just simple lists
			if (in_array($info['type'], array('varchar', 'char')) && $row['check_constraint']) {
				if (preg_match('/^\s*"?' . preg_quote($column, '/') . '"?\s+in\s+\((.*?)\)\s*$/i', $row['check_constraint'], $match)) {
					if (preg_match_all("/(?<!')'((''|[^']+)*)'/", $match[1], $matches, PREG_PATTERN_ORDER)) {
						$info['valid_values'] = str_replace("''", "'", $matches[1]);
					}			
				} elseif (preg_match('/^\s*"?' . preg_quote($column, '/') . '"?\s*=\s*\'((\'\'|[^\']+)*)\'(\s+OR\s+"?' . preg_quote($column, '/') . '"?\s*=\s*\'((\'\'|[^\']+)*)\')*\s*$/i', $row['check_constraint'], $match)) {
					if (preg_match_all("/(?<!')'((''|[^']+)*)'/", $row['check_constraint'], $matches, PREG_PATTERN_ORDER)) {
						$info['valid_values'] = str_replace("''", "'", $matches[1]);
					}			
				}
			}
			
			if (!$duplicate) {
				// Handle default values
				if ($row['data_default'] !== NULL && trim($row['data_default']) != 'NULL') {
					if (in_array($info['type'], array('date', 'time', 'timestamp')) && $row['data_default'][0] != "'") {
						$info['default'] = trim(preg_replace('#^SYS#', 'CURRENT_', $row['data_default']));
						
					} elseif (in_array($info['type'], array('char', 'varchar', 'text', 'date', 'time', 'timestamp'))) {
						$info['default'] = str_replace("''", "'", substr(trim($row['data_default']), 1, -1));
						
					} elseif ($info['type'] == 'boolean') {
						$info['default'] = (boolean) trim($row['data_default']);
						
					} elseif (in_array($info['type'], array('integer', 'float'))) {
						$info['default'] = trim($row['data_default']);
						
					} else {
						$info['default'] = $row['data_default'];
					}
				}
			
				// Not null values
				$info['not_null'] = ($row['nullable'] == 'N') ? TRUE : FALSE;
				
				$info['comment'] = $row['comments'];
			}
			
			$column_info[$column] = $info;
		}
		
		$sql = "SELECT
					TRIGGER_BODY
				FROM
					ALL_TRIGGERS
				WHERE
					TRIGGERING_EVENT LIKE 'INSERT%' AND
					STATUS = 'ENABLED' AND
					TRIGGER_NAME NOT LIKE 'BIN\$%' AND
					LOWER(TABLE_NAME) = %s AND
					LOWER(OWNER) = %s";
						
		foreach ($this->database->query($sql, $table, $schema) as $row) {
			if (preg_match('#SELECT\s+(["\w.]+).nextval\s+INTO\s+:new\.(\w+)\s+FROM\s+dual#i', $row['trigger_body'], $matches)) {
				$column = strtolower($matches[2]);
				$column_info[$column]['auto_increment'] = TRUE;
			}
		}
		
		return $column_info;
	}
	
	
	/**
	 * Fetches the key info for an Oracle database
	 * 
	 * @return array  The keys arrays for every table in the database - see ::getKeys() for details
	 */
	private function fetchOracleKeys()
	{
		$keys = array();
		
		$default_schema = strtolower($this->database->getUsername());
		
		$tables = $this->getTables();
		foreach ($tables as $table) {
			$keys[$table] = array();
			$keys[$table]['primary'] = array();
			$keys[$table]['unique']  = array();
			$keys[$table]['foreign'] = array();
		}
		
		$params = array();
		
		$sql  = "SELECT
					LOWER(AC.OWNER) \"SCHEMA\",
					LOWER(AC.TABLE_NAME) \"TABLE\",
					AC.CONSTRAINT_NAME CONSTRAINT_NAME,
					CASE AC.CONSTRAINT_TYPE
						WHEN 'P' THEN 'primary'
						WHEN 'R' THEN 'foreign'
						WHEN 'U' THEN 'unique'
						END TYPE,
					LOWER(ACC.COLUMN_NAME) \"COLUMN\",
					LOWER(FKC.OWNER) FOREIGN_SCHEMA,
					LOWER(FKC.TABLE_NAME) FOREIGN_TABLE,
					LOWER(FKC.COLUMN_NAME) FOREIGN_COLUMN,
					CASE WHEN FKC.TABLE_NAME IS NOT NULL THEN REPLACE(LOWER(AC.DELETE_RULE), ' ', '_') ELSE NULL END ON_DELETE
				FROM
					ALL_CONSTRAINTS AC INNER JOIN
					ALL_CONS_COLUMNS ACC ON AC.CONSTRAINT_NAME = ACC.CONSTRAINT_NAME AND AC.OWNER = ACC.OWNER LEFT JOIN
					ALL_CONSTRAINTS FK ON AC.R_CONSTRAINT_NAME = FK.CONSTRAINT_NAME AND AC.OWNER = FK.OWNER LEFT JOIN
					ALL_CONS_COLUMNS FKC ON FK.CONSTRAINT_NAME = FKC.CONSTRAINT_NAME AND FK.OWNER = FKC.OWNER
				WHERE
					AC.CONSTRAINT_TYPE IN ('U', 'P', 'R') AND ";
		
		$conditions = array();
		foreach ($tables as $table) {
			if (strpos($table, '.') === FALSE) {
				$table = $default_schema . '.' . $table;
			}	
			list ($schema, $table) = explode('.', strtolower($table));
			$conditions[] = "LOWER(AC.OWNER) = %s AND LOWER(AC.TABLE_NAME) = %s";
			$params[] = $schema;
			$params[] = $table;
		}
		$sql .= '((' . join(') OR( ', $conditions) . '))';
		
		$sql .= " ORDER BY
						 AC.OWNER ASC,
						 AC.TABLE_NAME ASC,
						 AC.CONSTRAINT_TYPE ASC,
						 AC.CONSTRAINT_NAME ASC,
						 ACC.POSITION ASC";
		
		$result = $this->database->query($sql, $params);
		
		$last_name  = '';
		$last_table = '';
		$last_type  = '';
		foreach ($result as $row) {
			
			if ($row['constraint_name'] != $last_name) {
				
				if ($last_name) {
					if ($last_type == 'foreign' || $last_type == 'unique') {
						$keys[$last_table][$last_type][] = $temp;
					} else {
						$keys[$last_table][$last_type] = $temp;
					}
				}
				
				$temp = array();
				if ($row['type'] == 'foreign') {
					
					$temp['column']         = $row['column'];
					$temp['foreign_table']  = $row['foreign_table'];
					if ($row['foreign_schema'] != $default_schema) {
						$temp['foreign_table'] = $row['foreign_schema'] . '.' . $temp['foreign_table'];
					}
					$temp['foreign_column'] = $row['foreign_column'];
					$temp['on_delete']      = 'no_action';
					$temp['on_update']      = 'no_action';
					
					if (!empty($row['on_delete'])) {
						$temp['on_delete'] = $row['on_delete'];
					}
					
				} else {
					$temp[] = $row['column'];
				}
				
				$last_table = $row['table'];
				if ($row['schema'] != $default_schema) {
					$last_table = $row['schema'] . '.' . $last_table;
				}
				$last_name  = $row['constraint_name'];
				$last_type  = $row['type'];
				
			} else {
				$temp[] = $row['column'];
			}
		}
		
		if (isset($temp)) {
			if ($last_type == 'foreign' || $last_type == 'unique') {
				$keys[$last_table][$last_type][] = $temp;
			} else {
				$keys[$last_table][$last_type] = $temp;
			}
		}
		
		return $keys;
	}
	
	
	/**
	 * Gets the column info from a PostgreSQL database
	 * 
	 * @param  string $table  The table to fetch the column info for
	 * @return array  The column info for the table specified - see ::getColumnInfo() for details
	 */
	private function fetchPostgreSQLColumnInfo($table)
	{
		$column_info = array();
		
		$schema = 'public';
		if (strpos($table, '.') !== FALSE) {
			list ($schema, $table) = explode('.', $table);	
		}
		
		$data_type_mapping = array(
			'boolean'			=> 'boolean',
			'smallint'			=> 'integer',
			'int'				=> 'integer',
			'bigint'			=> 'integer',
			'serial'			=> 'integer',
			'bigserial'			=> 'integer',
			'timestamp'			=> 'timestamp',
			'date'				=> 'date',
			'time'				=> 'time',
			'uuid'              => 'varchar',
			'character varying'	=> 'varchar',
			'character'			=> 'char',
			'real'				=> 'float',
			'double'			=> 'float',
			'numeric'			=> 'float',
			'bytea'				=> 'blob',
			'text'				=> 'text',
			'mediumtext'		=> 'text',
			'longtext'			=> 'text',
			'point'             => 'varchar',
			'line'              => 'varchar',
			'lseg'              => 'varchar',
			'box'               => 'varchar',
			'path'              => 'varchar',
			'polygon'           => 'varchar',
			'circle'            => 'varchar'
		);
		
		$max_min_values = array(
			'smallint'  => array('min' => new fNumber(-32768),                  'max' => new fNumber(32767)),
			'int'       => array('min' => new fNumber(-2147483648),             'max' => new fNumber(2147483647)),
			'bigint'    => array('min' => new fNumber('-9223372036854775808'),  'max' => new fNumber('9223372036854775807')),
			'serial'    => array('min' => new fNumber(-2147483648),             'max' => new fNumber(2147483647)),
			'bigserial' => array('min' => new fNumber('-9223372036854775808'),  'max' => new fNumber('9223372036854775807'))
		);
		
		// PgSQL required this complicated SQL to get the column info
		$sql = "SELECT
						LOWER(pg_attribute.attname)                                 AS column,
						format_type(pg_attribute.atttypid, pg_attribute.atttypmod)  AS data_type,
						pg_attribute.attnotnull                                     AS not_null,
						pg_attrdef.adsrc                                            AS default,
						pg_get_constraintdef(pg_constraint.oid)                     AS constraint,
						col_description(pg_class.oid, pg_attribute.attnum)          AS comment              
					FROM
						pg_attribute LEFT JOIN
						pg_class ON pg_attribute.attrelid = pg_class.oid LEFT JOIN
						pg_namespace ON pg_class.relnamespace = pg_namespace.oid LEFT JOIN
						pg_type ON pg_type.oid = pg_attribute.atttypid LEFT JOIN
						pg_constraint ON pg_constraint.conrelid = pg_class.oid AND
										 pg_attribute.attnum = ANY (pg_constraint.conkey) AND
										 pg_constraint.contype = 'c' LEFT JOIN
						pg_attrdef ON pg_class.oid = pg_attrdef.adrelid AND
									  pg_attribute.attnum = pg_attrdef.adnum
					WHERE
						NOT pg_attribute.attisdropped AND
						LOWER(pg_class.relname) = %s AND
						LOWER(pg_namespace.nspname) = %s AND
						pg_type.typname NOT IN ('oid', 'cid', 'xid', 'cid', 'xid', 'tid')
					ORDER BY
						pg_attribute.attnum,
						pg_constraint.contype";
		$result = $this->database->query($sql, strtolower($table), strtolower($schema));
		
		foreach ($result as $row) {
			
			$info = array();
			
			// Get the column type
			preg_match('#([\w ]+)\s*(?:\(\s*(\d+)(?:\s*,\s*(\d+))?\s*\))?#', $row['data_type'], $column_data_type);
			
			foreach ($data_type_mapping as $data_type => $mapped_data_type) {
				if (stripos($column_data_type[1], $data_type) === 0) {
					$info['type'] = $mapped_data_type;
					if (isset($max_min_values[$data_type])) {
						$info['min_value'] = $max_min_values[$data_type]['min'];
						$info['max_value'] = $max_min_values[$data_type]['max'];
					}
					break;
				}
			}
			
			if (!isset($info['type'])) {
				$info['type'] = $column_data_type[1];
			}
			
			if ($info['type'] == 'blob' || $info['type'] == 'text') {
				$info['max_length'] = 1073741824; 
			}
			
			// Handle the length of decimal/numeric fields
			if ($info['type'] == 'float' && isset($column_data_type[3]) && strlen($column_data_type[3]) > 0) {
				$info['decimal_places'] = (int) $column_data_type[3];
				$before_digits = str_pad('', $column_data_type[2] - $info['decimal_places'], '9');
				$after_digits  = str_pad('', $info['decimal_places'], '9');
				$max_min       = $before_digits . ($after_digits ? '.' : '') . $after_digits;
				$info['min_value'] = new fNumber('-' . $max_min);
				$info['max_value'] = new fNumber($max_min);
			}
			
			// Handle the special data for varchar fields
			if (in_array($info['type'], array('char', 'varchar'))) {
				if (!empty($column_data_type[2])) {
					$info['max_length'] = $column_data_type[2];
				} else {
					$info['max_length'] = 1073741824; 
				}
			}
			
			// In PostgreSQL, a UUID can be the 32 digits, 32 digits plus 4 hyphens or 32 digits plus 4 hyphens and 2 curly braces
			if ($row['data_type'] == 'uuid') {
				$info['max_length'] = 38;	
			}
			
			// Handle check constraints that are just simple lists
			if (in_array($info['type'], array('varchar', 'char')) && !empty($row['constraint'])) {
				if (preg_match('/CHECK[\( "]+' . $row['column'] . '[a-z\) ":]+\s+=\s+/i', $row['constraint'])) {
					if (preg_match_all("/(?!').'((''|[^']+)*)'/", $row['constraint'], $matches, PREG_PATTERN_ORDER)) {
						$info['valid_values'] = str_replace("''", "'", $matches[1]);
					}
				}
			}
			
			// Handle default values and serial data types
			if ($info['type'] == 'integer' && stripos($row['default'], 'nextval(') !== FALSE) {
				$info['auto_increment'] = TRUE;
				
			} elseif ($row['default'] !== NULL) {
				if (preg_match('#^NULL::[\w\s]+$#', $row['default'])) {
					$info['default'] = NULL;
				} elseif ($row['default'] == 'now()') {
					$info['default'] = 'CURRENT_TIMESTAMP';
				} elseif ($row['default'] == "('now'::text)::date") {
					$info['default'] = 'CURRENT_DATE';
				} elseif ($row['default'] == "('now'::text)::time with time zone") {
					$info['default'] = 'CURRENT_TIME';	
				} else {
					$info['default'] = str_replace("''", "'", preg_replace("/^'(.*)'::[a-z ]+\$/iD", '\1', $row['default']));
					if ($info['type'] == 'boolean') {
						$info['default'] = ($info['default'] == 'false' || !$info['default']) ? FALSE : TRUE;
					}
				}
			}
			
			// Not null values
			$info['not_null'] = ($row['not_null'] == 't') ? TRUE : FALSE;
			
			$info['comment'] = $row['comment'];
			
			$column_info[$row['column']] = $info;
		}
		
		return $column_info;
	}
	
	
	/**
	 * Fetches the key info for a PostgreSQL database
	 * 
	 * @return array  The keys arrays for every table in the database - see ::getKeys() for details
	 */
	private function fetchPostgreSQLKeys()
	{
		$keys = array();
		
		$tables   = $this->getTables();
		foreach ($tables as $table) {
			$keys[$table] = array();
			$keys[$table]['primary'] = array();
			$keys[$table]['unique']  = array();
			$keys[$table]['foreign'] = array();
		}
		
		$sql  = "(
				SELECT
					LOWER(s.nspname) AS \"schema\",
					LOWER(t.relname) AS \"table\",
					con.conname AS constraint_name,
					CASE con.contype
						WHEN 'f' THEN 'foreign'
						WHEN 'p' THEN 'primary'
						WHEN 'u' THEN 'unique'
					END AS type,
					LOWER(col.attname) AS column,
					LOWER(fs.nspname) AS foreign_schema,
					LOWER(ft.relname) AS foreign_table,
					LOWER(fc.attname) AS foreign_column,
					CASE con.confdeltype
						WHEN 'c' THEN 'cascade'
						WHEN 'a' THEN 'no_action'
						WHEN 'r' THEN 'restrict'
						WHEN 'n' THEN 'set_null'
						WHEN 'd' THEN 'set_default'
					END AS on_delete,
					CASE con.confupdtype
						WHEN 'c' THEN 'cascade'
						WHEN 'a' THEN 'no_action'
						WHEN 'r' THEN 'restrict'
						WHEN 'n' THEN 'set_null'
						WHEN 'd' THEN 'set_default'
					END AS on_update,
					CASE WHEN con.conkey IS NOT NULL THEN position('-'||col.attnum||'-' in '-'||array_to_string(con.conkey, '-')||'-') ELSE 0 END AS column_order
				FROM
					pg_attribute AS col INNER JOIN
					pg_class AS t ON
						col.attrelid = t.oid INNER JOIN
					pg_namespace AS s ON
						t.relnamespace = s.oid INNER JOIN
					pg_constraint AS con ON
						col.attnum = ANY (con.conkey) AND
						con.conrelid = t.oid LEFT JOIN
					pg_class AS ft ON
						con.confrelid = ft.oid LEFT JOIN
					pg_namespace AS fs ON
						ft.relnamespace = fs.oid LEFT JOIN
					pg_attribute AS fc ON
						fc.attnum = ANY (con.confkey) AND
						ft.oid = fc.attrelid
				WHERE
					NOT col.attisdropped AND
					(con.contype = 'p' OR
					con.contype = 'f' OR
					con.contype = 'u')
				) UNION (
				SELECT
					LOWER(n.nspname) AS \"schema\",
					LOWER(t.relname) AS \"table\",
					ic.relname AS constraint_name,
					'unique' AS type,
					LOWER(col.attname) AS column,
					NULL AS foreign_schema,
					NULL AS foreign_table,
					NULL AS foreign_column,
					NULL AS on_delete,
					NULL AS on_update,
					CASE WHEN ind.indkey IS NOT NULL THEN position('-'||col.attnum||'-' in '-'||array_to_string(ind.indkey, '-')||'-') ELSE 0 END AS column_order
				FROM
					pg_class AS t INNER JOIN
					pg_index AS ind ON
						ind.indrelid = t.oid INNER JOIN
					pg_namespace AS n ON
						t.relnamespace = n.oid INNER JOIN
					pg_class AS ic ON
						ind.indexrelid = ic.oid LEFT JOIN
					pg_constraint AS con ON
						con.conrelid = t.oid AND
						con.contype = 'u' AND
						con.conname = ic.relname INNER JOIN
					pg_attribute AS col ON
						col.attrelid = t.oid AND
						col.attnum = ANY (ind.indkey)  
				WHERE
					n.nspname NOT IN ('pg_catalog', 'pg_toast') AND
					indisunique = TRUE AND
					indisprimary = FALSE AND
					con.oid IS NULL AND
					0 != ALL ((ind.indkey)::int[])
			) ORDER BY 1, 2, 4, 3, 11";
		
		$result = $this->database->query($sql);
		
		$last_name  = '';
		$last_table = '';
		$last_type  = '';
		foreach ($result as $row) {
			
			if ($row['constraint_name'] != $last_name) {
				
				if ($last_name) {
					if ($last_type == 'foreign' || $last_type == 'unique') {
						$keys[$last_table][$last_type][] = $temp;
					} else {
						$keys[$last_table][$last_type] = $temp;
					}
				}
				
				$temp = array();
				if ($row['type'] == 'foreign') {
					
					$temp['column']         = $row['column'];
					$temp['foreign_table']  = $row['foreign_table'];
					if ($row['foreign_schema'] != 'public') {
						$temp['foreign_table'] = $row['foreign_schema'] . '.' . $temp['foreign_table'];	
					}
					$temp['foreign_column'] = $row['foreign_column'];
					$temp['on_delete']      = 'no_action';
					$temp['on_update']      = 'no_action';
					
					if (!empty($row['on_delete'])) {
						$temp['on_delete'] = $row['on_delete'];
					}
					
					if (!empty($row['on_update'])) {
						$temp['on_update'] = $row['on_update'];
					}
					
				} else {
					$temp[] = $row['column'];
				}
				
				$last_table = $row['table'];
				if ($row['schema'] != 'public') {
					$last_table = $row['schema'] . '.' . $last_table;	
				}
				$last_name  = $row['constraint_name'];
				$last_type  = $row['type'];
				
			} else {
				$temp[] = $row['column'];
			}
		}
		
		if (isset($temp)) {
			if ($last_type == 'foreign' || $last_type == 'unique') {
				$keys[$last_table][$last_type][] = $temp;
			} else {
				$keys[$last_table][$last_type] = $temp;
			}
		}
		
		return $keys;
	}
	
	
	/**
	 * Gets the column info from a SQLite database
	 * 
	 * @param  string $table  The table to fetch the column info for
	 * @return array  The column info for the table specified - see ::getColumnInfo() for details
	 */
	private function fetchSQLiteColumnInfo($table)
	{
		$column_info = array();
		
		$data_type_mapping = array(
			'boolean'			=> 'boolean',
			'serial'            => 'integer',
			'smallint'			=> 'integer',
			'int'				=> 'integer',
			'integer'           => 'integer',
			'bigint'			=> 'integer',
			'timestamp'			=> 'timestamp',
			'date'				=> 'date',
			'time'				=> 'time',
			'varchar'			=> 'varchar',
			'char'				=> 'char',
			'real'				=> 'float',
			'numeric'           => 'float',
			'float'             => 'float',
			'double'			=> 'float',
			'decimal'			=> 'float',
			'blob'				=> 'blob',
			'text'				=> 'text'
		);
		
		$result = $this->database->query("SELECT sql FROM sqlite_master WHERE type = 'table' AND LOWER(name) = %s", strtolower($table));
		
		try {
			$row        = $result->fetchRow();
			$create_sql = $row['sql'];
		} catch (fNoRowsException $e) {
			return array();			
		}
		
		preg_match_all('#(?<=,|\(|\*/|\n)\s*(?:`|"|\[)?(\w+)(?:`|"|\])?\s+([a-z]+)(?:\(\s*(\d+)(?:\s*,\s*(\d+))?\s*\))?(?:(\s+NOT\s+NULL)|(?:\s+NULL)|(?:\s+DEFAULT\s+([^, \'\n]*|\'(?:\'\'|[^\']+)*\'))|(\s+UNIQUE)|(\s+PRIMARY\s+KEY(?:\s+AUTOINCREMENT)?)|(\s+CHECK\s*\("?\w+"?\s+IN\s+\(\s*(?:(?:[^, \'\n]+|\'(?:\'\'|[^\']+)*\')\s*,\s*)*\s*(?:[^, \'\n]+|\'(?:\'\'|[^\']+)*\')\)\)))*(\s+REFERENCES\s+["`\[]?\w+["`\]]?\s*\(\s*["`\[]?\w+["`\]]?\s*\)\s*(?:\s+(?:ON\s+DELETE|ON\s+UPDATE)\s+(?:CASCADE|NO\s+ACTION|RESTRICT|SET\s+NULL|SET\s+DEFAULT))*(?:\s+(?:DEFERRABLE|NOT\s+DEFERRABLE))?)?([ \t]*(?:/\*(?:(?!\*/).)*\*/))?\s*(?:,([ \t]*--[^\n]*\n)?|(--[^\n]*\n)?\s*(?:/\*(?:(?!\*/).)*\*/)?\s*(?=\)))#msi', $create_sql, $matches, PREG_SET_ORDER);
		
		foreach ($matches as $match) {
			$info = array();
			
			foreach ($data_type_mapping as $data_type => $mapped_data_type) {
				if (stripos($match[2], $data_type) === 0) {
					$info['type'] = $mapped_data_type;
					break;
				}
			}
		
			// Type specific information
			if (in_array($info['type'], array('char', 'varchar'))) {
				if (!empty($match[3])) {
					$info['max_length'] = $match[3];
				} else {
					$info['max_length'] = 1000000000;   
				}
			}
			
			if ($info['type'] == 'text' || $info['type'] == 'blob') {
				$info['max_length'] = 1000000000;   
			}
			
			// Figure out how many decimal places for a decimal
			if (in_array(strtolower($match[2]), array('decimal', 'numeric')) && !empty($match[4])) {
				$info['decimal_places'] = $match[4];
				$before_digits = str_pad('', $match[3] - $match[4], '9');
				$after_digits  = str_pad('', $match[4], '9');
				$max_min       = $before_digits . ($after_digits ? '.' : '') . $after_digits;
				$info['min_value'] = new fNumber('-' . $max_min);
				$info['max_value'] = new fNumber($max_min);
			}
			
			// Not null
			$info['not_null'] = (!empty($match[5]) || !empty($match[8])) ? TRUE : FALSE;
		
			// Default values
			if (isset($match[6]) && $match[6] != '' && $match[6] != 'NULL') {
				$info['default'] = preg_replace("/^'|'\$/D", '', $match[6]);
			}
			if ($info['type'] == 'boolean' && isset($info['default'])) {
				$info['default'] = ($info['default'] == 'f' || $info['default'] == 0 || $info['default'] == 'false') ? FALSE : TRUE;
			}
		
			// Check constraints
			if (isset($match[9]) && preg_match('/CHECK\s*\(\s*"?' . $match[1] . '"?\s+IN\s+\(\s*((?:(?:[^, \']*|\'(?:\'\'|[^\']+)*\')\s*,\s*)*(?:[^, \']*|\'(?:\'\'|[^\']+)*\'))\s*\)/i', $match[9], $check_match)) {
				$info['valid_values'] = str_replace("''", "'", preg_replace("/^'|'\$/D", '', preg_split("#\s*,\s*#", $check_match[1])));
			}
		
			// Auto increment fields
			if (!empty($match[8]) && (stripos($match[8], 'autoincrement') !== FALSE || $info['type'] == 'integer')) {
				$info['auto_increment'] = TRUE;
			}
			
			// Column comments
			if (!empty($match[11]) || !empty($match[12]) || !empty($match[13])) {
				if (!empty($match[11])) {
					$comment = $match[11];
				} elseif (!empty($match[12])) {
					$comment = $match[12];
				} else {
					$comment = $match[13];
				}
				$comment = trim($comment);
				$comment = substr($comment, 0, 2) == '--' ? substr($comment, 2) : substr($comment, 2, -2);
				$info['comment'] = trim($comment);
			}
		
			$column_info[strtolower($match[1])] = $info;
		}
		
		return $column_info;
	}
	
	
	/**
	 * Fetches the key info for an SQLite database
	 * 
	 * @return array  The keys arrays for every table in the database - see ::getKeys() for details
	 */
	private function fetchSQLiteKeys()
	{
		$tables = $this->getTables();
		$keys   = array();
		
		foreach ($tables as $table) {
			$keys[$table] = array();
			$keys[$table]['primary'] = array();
			$keys[$table]['foreign'] = array();
			$keys[$table]['unique']  = array();
			
			$result     = $this->database->query("SELECT sql FROM sqlite_master WHERE type = 'table' AND LOWER(name) = %s", strtolower($table));
			$row        = $result->fetchRow();
			$create_sql = $row['sql'];

			// Collapse strings into empty string to make the matching simpler
			$create_sql = preg_replace('#\'(?:\'\'|[^\']+)*\'#', "''", $create_sql);
			
			// Remove single-line comments
			$create_sql = preg_replace('#--[^\n]*\n#', "\n", $create_sql);
			
			// Remove multi-line comments
			$create_sql = preg_replace('#/\*((?!\*/).)*\*/#', '', $create_sql);
			
			// Get column level key definitions
			preg_match_all('#(?<=,|\()\s*["`\[]?(\w+)["`\]]?\s+(?:[a-z]+)(?:\((?:\d+)\))?(?:(?:\s+NOT\s+NULL)|(?:\s+DEFAULT\s+(?:[^, \']*|\'(?:\'\'|[^\']+)*\'))|(\s+UNIQUE)|(\s+PRIMARY\s+KEY(?:\s+AUTOINCREMENT)?)|(?:\s+CHECK\s*\("?\w+"?\s+IN\s+\(\s*(?:(?:[^, \']+|\'(?:\'\'|[^\']+)*\')\s*,\s*)*\s*(?:[^, \']+|\'(?:\'\'|[^\']+)*\')\)\)))*(\s+REFERENCES\s+["`\[]?(\w+)["`\]]?\s*\(\s*["`\[]?(\w+)["`\]]?\s*\)\s*(?:(?:\s+(?:ON\s+DELETE\s+(CASCADE|NO\s+ACTION|RESTRICT|SET\s+NULL|SET\s+DEFAULT)))|(?:\s+(?:ON\s+UPDATE\s+(CASCADE|NO\s+ACTION|RESTRICT|SET\s+NULL|SET\s+DEFAULT))))*(?:\s+(?:DEFERRABLE|NOT\s+DEFERRABLE))?)?\s*(?:,|\s*(?=\)))#mi', $create_sql, $matches, PREG_SET_ORDER);
			
			foreach ($matches as $match) {
				if (!empty($match[2])) {
					$keys[$table]['unique'][] = array(strtolower($match[1]));
				}
				
				if (!empty($match[3])) {
					$keys[$table]['primary'] = array(strtolower($match[1]));
				}
				
				if (!empty($match[4])) {
					$temp = array(
						'column'         => strtolower($match[1]),
						'foreign_table'  => strtolower($match[5]),
						'foreign_column' => strtolower($match[6]),
						'on_delete'      => 'no_action',
						'on_update'      => 'no_action'
					);
					if (isset($match[7])) {
						$temp['on_delete'] = strtolower(str_replace(' ', '_', $match[7]));
					}
					if (isset($match[8])) {
						$temp['on_update'] = strtolower(str_replace(' ', '_', $match[8]));
					}
					$keys[$table]['foreign'][] = $temp;
				}
			}
			
			// Get table level primary key definitions
			preg_match_all('#(?<=,|\()\s*(?:CONSTRAINT\s+["`\[]?\w+["`\]]?\s+)?PRIMARY\s+KEY\s*\(\s*((?:\s*["`\[]?\w+["`\]]?\s*,\s*)*["`\[]?\w+["`\]]?)\s*\)\s*(?:,|\s*(?=\)))#mi', $create_sql, $matches, PREG_SET_ORDER);
			
			foreach ($matches as $match) {
				$columns = preg_split('#\s*,\s*#', strtolower($match[1]));
				foreach ($columns as $column) {
					$keys[$table]['primary'][] = str_replace(array('[', '"', '`', ']'), '', $column);	
				}
			}
			
			// Get table level foreign key definitions
			preg_match_all('#(?<=,|\()\s*(?:CONSTRAINT\s+["`\[]?\w+["`\]]?\s+)?FOREIGN\s+KEY\s*(?:["`\[]?(\w+)["`\]]?|\(\s*["`\[]?(\w+)["`\]]?\s*\))\s+REFERENCES\s+["`\[]?(\w+)["`\]]?\s*\(\s*["`\[]?(\w+)["`\]]?\s*\)\s*(?:\s+(?:ON\s+DELETE\s+(CASCADE|NO\s+ACTION|RESTRICT|SET\s+NULL|SET\s+DEFAULT))|\s+(?:ON\s+UPDATE\s+(CASCADE|NO\s+ACTION|RESTRICT|SET\s+NULL|SET\s+DEFAULT)))*(?:\s+(?:DEFERRABLE|NOT\s+DEFERRABLE))?\s*(?:,|\s*(?=\)))#mis', $create_sql, $matches, PREG_SET_ORDER);
			
			foreach ($matches as $match) {
				if (empty($match[1])) { $match[1] = $match[2]; }
				$temp = array(
					'column'         => strtolower($match[1]),
					'foreign_table'  => strtolower($match[3]),
					'foreign_column' => strtolower($match[4]),
					'on_delete'      => 'no_action',
					'on_update'      => 'no_action'
				);
				if (isset($match[5])) {
					$temp['on_delete'] = strtolower(str_replace(' ', '_', $match[5]));
				}
				if (isset($match[6])) {
					$temp['on_update'] = strtolower(str_replace(' ', '_', $match[6]));
				}
				$keys[$table]['foreign'][] = $temp;
			}
			
			// Get table level unique key definitions
			preg_match_all('#(?<=,|\()\s*(?:CONSTRAINT\s+["`\[]?\w+["`\]]?\s+)?UNIQUE\s*\(\s*((?:\s*["`\[]?\w+["`\]]?\s*,\s*)*["`\[]?\w+["`\]]?)\s*\)\s*(?:,|\s*(?=\)))#mi', $create_sql, $matches, PREG_SET_ORDER);
			
			foreach ($matches as $match) {
				$columns = preg_split('#\s*,\s*#', strtolower($match[1]));
				$key = array();
				foreach ($columns as $column) {
					$key[] = str_replace(array('[', '"', '`', ']'), '', $column);
				}
				$keys[$table]['unique'][] = $key;
			}
			
			// Get all CREATE UNIQUE INDEX statements
			$result = $this->database->query("SELECT sql FROM sqlite_master WHERE type = 'index' AND sql <> '' AND LOWER(tbl_name) = %s", strtolower($table));
			foreach ($result as $row) {
				$create_sql = $row['sql'];
				if (!preg_match('#^\s*CREATE\s+UNIQUE\s+INDEX\s+(?:["`\[]?\w+["`\]]?\.)?["`\[]?\w+["`\]]?\s+ON\s+[\'"`\[]?\w+[\'"`\]]?\s*\(\s*((?:\s*["`\[]?\w+["`\]]?\s*,\s*)*["`\[]?\w+["`\]]?)\s*\)\s*$#Di', $create_sql, $match)) {
					continue;
				}
				$columns = preg_split('#\s*,\s*#', strtolower($match[1]));
				$key = array();
				foreach ($columns as $column) {
					$key[] = str_replace(array('[', '"', '`', ']'), '', $column);
				}
				$keys[$table]['unique'][] = $key;
			}
		}
		
		return $keys;
	}
	
	
	/**
	 * Finds many-to-many relationship for the table specified
	 * 
	 * @param  string $table  The table to find the relationships on
	 * @return void
	 */
	private function findManyToManyRelationships($table)
	{
		if (!$this->isJoiningTable($table)) {
			return;
		}
		
		list ($key1, $key2) = $this->merged_keys[$table]['foreign'];
		
		$temp = array();
		$temp['table']               = $key1['foreign_table'];
		$temp['column']              = $key1['foreign_column'];
		$temp['related_table']       = $key2['foreign_table'];
		$temp['related_column']      = $key2['foreign_column'];
		$temp['join_table']          = $table;
		$temp['join_column']         = $key1['column'];
		$temp['join_related_column'] = $key2['column'];
		$temp['on_update']           = $key1['on_update'];
		$temp['on_delete']           = $key1['on_delete'];
		$this->relationships[$key1['foreign_table']]['many-to-many'][] = $temp;
		
		$temp = array();
		$temp['table']               = $key2['foreign_table'];
		$temp['column']              = $key2['foreign_column'];
		$temp['related_table']       = $key1['foreign_table'];
		$temp['related_column']      = $key1['foreign_column'];
		$temp['join_table']          = $table;
		$temp['join_column']         = $key2['column'];
		$temp['join_related_column'] = $key1['column'];
		$temp['on_update']           = $key2['on_update'];
		$temp['on_delete']           = $key2['on_delete'];
		$this->relationships[$key2['foreign_table']]['many-to-many'][] = $temp;
	}
	
	
	/**
	 * Finds one-to-many relationship for the table specified
	 * 
	 * @param  string $table  The table to find the relationships on
	 * @return void
	 */
	private function findOneToManyRelationships($table)
	{
		foreach ($this->merged_keys[$table]['foreign'] as $key) {
			$type = ($this->checkForSingleColumnUniqueKey($table, $key['column'])) ? 'one-to-one' : 'one-to-many';
			$temp = array();
			$temp['table']          = $key['foreign_table'];
			$temp['column']         = $key['foreign_column'];
			$temp['related_table']  = $table;
			$temp['related_column'] = $key['column'];
			$temp['on_delete']      = $key['on_delete'];
			$temp['on_update']      = $key['on_update'];
			$this->relationships[$key['foreign_table']][$type][] = $temp;
		}
	}
	
	
	/**
	 * Finds one-to-one and many-to-one relationship for the table specified
	 * 
	 * @param  string $table  The table to find the relationships on
	 * @return void
	 */
	private function findStarToOneRelationships($table)
	{
		foreach ($this->merged_keys[$table]['foreign'] as $key) {
			$temp = array();
			$temp['table']          = $table;
			$temp['column']         = $key['column'];
			$temp['related_table']  = $key['foreign_table'];
			$temp['related_column'] = $key['foreign_column'];
			$type = ($this->checkForSingleColumnUniqueKey($table, $key['column'])) ? 'one-to-one' : 'many-to-one';
			if ($type == 'one-to-one') {
				$temp['on_delete'] = $key['on_delete'];
				$temp['on_update'] = $key['on_update'];	
			}
			$this->relationships[$table][$type][] = $temp;
		}
	}
	
	
	/**
	 * Finds the one-to-one, many-to-one, one-to-many and many-to-many relationships in the database
	 * 
	 * @return void
	 */
	private function findRelationships()
	{
		$this->relationships = array();
		$tables = $this->getTables();
		
		foreach ($tables as $table) {
			$this->relationships[$table]['one-to-one']   = array();
			$this->relationships[$table]['many-to-one']  = array();
			$this->relationships[$table]['one-to-many']  = array();
			$this->relationships[$table]['many-to-many'] = array();
		}
		
		// Calculate the relationships
		foreach ($this->merged_keys as $table => $keys) {
			$this->findManyToManyRelationships($table);
			if ($this->isJoiningTable($table)) {
				continue;
			}
			
			$this->findStarToOneRelationships($table);
			$this->findOneToManyRelationships($table);
		}
		
		if ($this->cache) {
			$this->cache->set($this->makeCachePrefix() . 'relationships', $this->relationships);	
		}
	}
	
	
	/**
	 * Returns column information for the table specified
	 * 
	 * If only a table is specified, column info is in the following format:
	 * 
	 * {{{
	 * array(
	 *     (string) {column name} => array(
	 *         'type'           => (string)  {data type},
	 *         'placeholder'    => (string)  {fDatabase::escape() placeholder for this data type},
	 *         'not_null'       => (boolean) {if value can't be null},
	 *         'default'        => (mixed)   {the default value},
	 *         'valid_values'   => (array)   {the valid values for a varchar field},
	 *         'max_length'     => (integer) {the maximum length in a varchar field},
	 *         'min_value'      => (numeric) {the minimum value for an integer/float field},
	 *         'max_value'      => (numeric) {the maximum value for an integer/float field},
	 *         'decimal_places' => (integer) {the number of decimal places for a decimal/numeric/money/smallmoney field},
	 *         'auto_increment' => (boolean) {if the integer primary key column is a serial/autoincrement/auto_increment/indentity column},
	 *         'comment'        => (string)  {the SQL comment/description for the column}
	 *     ), ...
	 * )
	 * }}}
	 * 
	 * If a table and column are specified, column info is in the following format:
	 * 
	 * {{{
	 * array(
	 *     'type'           => (string)  {data type},
	 *     'placeholder'    => (string)  {fDatabase::escape() placeholder for this data type},
	 *     'not_null'       => (boolean) {if value can't be null},
	 *     'default'        => (mixed)   {the default value-may contain special strings CURRENT_TIMESTAMP, CURRENT_TIME or CURRENT_DATE},
	 *     'valid_values'   => (array)   {the valid values for a varchar field},
	 *     'max_length'     => (integer) {the maximum length in a char/varchar field},
	 *     'min_value'      => (fNumber) {the minimum value for an integer/float field},
	 *     'max_value'      => (fNumber) {the maximum value for an integer/float field},
	 *     'decimal_places' => (integer) {the number of decimal places for a decimal/numeric/money/smallmoney field},
	 *     'auto_increment' => (boolean) {if the integer primary key column is a serial/autoincrement/auto_increment/indentity column},
	 *     'comment'        => (string)  {the SQL comment/description for the column}
	 * )
	 * }}}
	 * 
	 * If a table, column and element are specified, returned value is the single element specified.
	 * 
	 * The `'type'` element is homogenized to a value from the following list:
	 * 
	 *  - `'varchar'`
	 *  - `'char'`
	 *  - `'text'`
	 *  - `'integer'`
	 *  - `'float'`
	 *  - `'timestamp'`
	 *  - `'date'`
	 *  - `'time'`
	 *  - `'boolean'`
	 *  - `'blob'`
	 * 
	 * Please note that MySQL reports boolean data types as `tinyint(1)`, so
	 * all `tinyint(1)` columns will be listed as `boolean`. This can be fixed
	 * by calling: 
	 * 
	 * {{{
	 * #!php
	 * $schema->setColumnInfoOverride(
	 *     array(
	 *         'type'        => 'integer',
	 *         'placeholder' => '%i',
	 *         'default'     => {default integer},
	 *         'min_value'   => new fNumber(-128),
	 *         'max_value'   => new fNumber(127)
	 *     ),
	 *     '{table name}',
	 *     '{column name}'
	 * );
	 * }}}
	 * 
	 * The `'comment'` element pulls from the database's column comment facility
	 * with the exception of MSSQL and SQLite.
	 * 
	 * For MSSQL, the comment is pulled from the `MS_Description` extended
	 * property, which can be added via the `Description` field in SQL Server
	 * Management Studio, or via the `sp_addextendedproperty` stored procedure.
	 * 
	 * For SQLite, the comment is extracted from any SQL comment that is placed
	 * at the end of the line on which the column is defined:
	 * 
	 * {{{
	 * #!sql
	 * CREATE TABLE users (
	 *     user_id INTEGER PRIMARY KEY AUTOINCREMENT,
	 *     name VARCHAR(200) NOT NULL -- This is the full name
	 * );
	 * }}}
	 * 
	 * For the SQLite `users` table defined above, the `name` column will have
	 * the comment `This is the full name`.
	 * 
	 * @param  string $table    The table to get the column info for
	 * @param  string $column   The column to get the info for
	 * @param  string $element  The element to return: `'type'`, `'placeholder'`, `'not_null'`, `'default'`, `'valid_values'`, `'max_length'`, `'min_value'`, `'max_value'`, `'decimal_places'`, `'auto_increment'`, `'comment'`
	 * @return mixed  The column info for the table/column/element specified - see method description for format
	 */
	public function getColumnInfo($table, $column=NULL, $element=NULL)
	{
		$table = strtolower($table);
		if ($column !== NULL) {
			$column = strtolower($column);
		}

		// Return the saved column info if possible
		if (!$column && isset($this->merged_column_info[$table])) {
			return $this->merged_column_info[$table];
		}
		if ($column && isset($this->merged_column_info[$table][$column])) {
			if ($element !== NULL) {
				if (!isset($this->merged_column_info[$table][$column][$element]) && !array_key_exists($element, $this->merged_column_info[$table][$column])) {
					throw new fProgrammerException(
						'The element specified, %1$s, is invalid. Must be one of: %2$s.',
						$element,
						join(', ', array('type', 'placeholder', 'not_null', 'default', 'valid_values', 'max_length', 'min_value', 'max_value', 'decimal_places', 'auto_increment'))
					);	
				}
				return $this->merged_column_info[$table][$column][$element];
			}
			return $this->merged_column_info[$table][$column];
		}
		
		if (!in_array($table, $this->getTables())) {
			throw new fProgrammerException(
				'The table specified, %s, does not exist in the database',
				$table
			);
		}
		
		$this->fetchColumnInfo($table);
		$this->mergeColumnInfo();
		
		if ($column && !isset($this->merged_column_info[$table][$column])) {
			throw new fProgrammerException(
				'The column specified, %1$s, does not exist in the table %2$s',
				$column,
				$table
			);
		}
		
		if ($column) {
			if ($element) {
				return $this->merged_column_info[$table][$column][$element];
			}
			
			return $this->merged_column_info[$table][$column];
		}
		
		return $this->merged_column_info[$table];
	}
	
	
	/**
	 * Returns the databases on the current server
	 * 
	 * @return array  The databases on the current server
	 */
	public function getDatabases()
	{
		if ($this->databases !== NULL) {
			return $this->databases;
		}
		
		$this->databases = array();
		
		switch ($this->database->getType()) {
			case 'mssql':
				$sql = 'EXECUTE sp_databases';
				break;
			
			case 'mysql':
				$sql = 'SHOW DATABASES';
				break;
				
			case 'oracle':
				$sql = 'SELECT ora_database_name FROM dual';
			
			case 'postgresql':
				$sql = "SELECT
							datname
						FROM
							pg_database
						ORDER BY
							LOWER(datname)";
				break;
								
			case 'db2':
				$this->databases[] = strtolower($this->database->getDatabase());
				return $this->databases;

			case 'sqlite':
				$this->databases[] = $this->database->getDatabase();
				return $this->databases;
		}
		
		$result = $this->database->query($sql);
		
		foreach ($result as $row) {
			$keys = array_keys($row);
			$this->databases[] = strtolower($row[$keys[0]]);
		}
		
		if ($this->cache) {
			$this->cache->set($this->makeCachePrefix() . 'databases', $this->databases);		
		}
		
		return $this->databases;
	}
	
	
	/**
	 * Returns a list of primary key, foreign key and unique key constraints for the table specified
	 * 
	 * The structure of the returned array is:
	 * 
	 * {{{
	 * array(
	 *      'primary' => array(
	 *          {column name}, ...
	 *      ),
	 *      'unique'  => array(
	 *          array(
	 *              {column name}, ...
	 *          ), ...
	 *      ),
	 *      'foreign' => array(
	 *          array(
	 *              'column'         => {column name},
	 *              'foreign_table'  => {foreign table name},
	 *              'foreign_column' => {foreign column name},
	 *              'on_delete'      => {the ON DELETE action: 'no_action', 'restrict', 'cascade', 'set_null', or 'set_default'},
	 *              'on_update'      => {the ON UPDATE action: 'no_action', 'restrict', 'cascade', 'set_null', or 'set_default'}
	 *          ), ...
	 *      )
	 * )
	 * }}}
	 * 
	 * @param  string $table     The table to return the keys for
	 * @param  string $key_type  The type of key to return: `'primary'`, `'foreign'`, `'unique'`
	 * @return array  An array of all keys, or just the type specified - see method description for format
	 */
	public function getKeys($table, $key_type=NULL)
	{
		$table           = strtolower($table);
		$valid_key_types = array('primary', 'foreign', 'unique');
		if ($key_type !== NULL && !in_array($key_type, $valid_key_types)) {
			throw new fProgrammerException(
				'The key type specified, %1$s, is invalid. Must be one of: %2$s.',
				$key_type,
				join(', ', $valid_key_types)
			);
		}
		
		// Return the saved column info if possible
		if (!$key_type && isset($this->merged_keys[$table])) {
			reset($this->merged_keys[$table]);
			return $this->merged_keys[$table];
		}
		
		if ($key_type && isset($this->merged_keys[$table][$key_type])) {
			reset($this->merged_keys[$table][$key_type]);
			return $this->merged_keys[$table][$key_type];
		}
		
		if (!in_array($table, $this->getTables())) {
			throw new fProgrammerException(
				'The table specified, %s, does not exist in the database',
				$table
			);
		}
		
		$this->fetchKeys();
		$this->mergeKeys();
		
		if ($key_type) {
			reset($this->merged_keys[$table][$key_type]);
			return $this->merged_keys[$table][$key_type];
		}
		
		reset($this->merged_keys[$table]);
		return $this->merged_keys[$table];
	}
	
	
	/**
	 * Returns a list of one-to-one, many-to-one, one-to-many and many-to-many relationships for the table specified
	 * 
	 * The structure of the returned array is:
	 * 
	 * {{{
	 * array(
	 *     'one-to-one' => array(
	 *         array(
	 *             'table'          => (string) {the name of the table this relationship is for},
	 *             'column'         => (string) {the column in the specified table},
	 *             'related_table'  => (string) {the related table},
	 *             'related_column' => (string) {the related column},
	 *             'on_delete'      => (string) {the ON DELETE action: 'no_action', 'restrict', 'cascade', 'set_null', or 'set_default'},
	 *             'on_update'      => (string) {the ON UPDATE action: 'no_action', 'restrict', 'cascade', 'set_null', or 'set_default'}
	 *         ), ...
	 *     ),
	 *     'many-to-one' => array(
	 *         array(
	 *             'table'          => (string) {the name of the table this relationship is for},
	 *             'column'         => (string) {the column in the specified table},
	 *             'related_table'  => (string) {the related table},
	 *             'related_column' => (string) {the related column}
	 *         ), ...
	 *     ),
	 *     'one-to-many' => array(
	 *         array(
	 *             'table'          => (string) {the name of the table this relationship is for},
	 *             'column'         => (string) {the column in the specified table},
	 *             'related_table'  => (string) {the related table},
	 *             'related_column' => (string) {the related column},
	 *             'on_delete'      => (string) {the ON DELETE action: 'no_action', 'restrict', 'cascade', 'set_null', or 'set_default'},
	 *             'on_update'      => (string) {the ON UPDATE action: 'no_action', 'restrict', 'cascade', 'set_null', or 'set_default'}
	 *         ), ...
	 *     ),
	 *     'many-to-many' => array(
	 *         array(
	 *             'table'               => (string) {the name of the table this relationship is for},
	 *             'column'              => (string) {the column in the specified table},
	 *             'related_table'       => (string) {the related table},
	 *             'related_column'      => (string) {the related column},
	 *             'join_table'          => (string) {the table that joins the specified table to the related table},
	 *             'join_column'         => (string) {the column in the join table that references 'column'},
	 *             'join_related_column' => (string) {the column in the join table that references 'related_column'},
	 *             'on_delete'           => (string) {the ON DELETE action: 'no_action', 'restrict', 'cascade', 'set_null', or 'set_default'},
	 *             'on_update'           => (string) {the ON UPDATE action: 'no_action', 'restrict', 'cascade', 'set_null', or 'set_default'}
	 *         ), ...
	 *     )
	 * )
	 * }}}
	 * 
	 * @param  string $table              The table to return the relationships for
	 * @param  string $relationship_type  The type of relationship to return: `'one-to-one'`, `'many-to-one'`, `'one-to-many'`, `'many-to-many'`
	 * @return array  An array of all relationships, or just the type specified - see method description for format
	 */
	public function getRelationships($table, $relationship_type=NULL)
	{
		$table = strtolower($table);

		$valid_relationship_types = array('one-to-one', 'many-to-one', 'one-to-many', 'many-to-many');
		if ($relationship_type !== NULL && !in_array($relationship_type, $valid_relationship_types)) {
			throw new fProgrammerException(
				'The relationship type specified, %1$s, is invalid. Must be one of: %2$s.',
				$relationship_type,
				join(', ', $valid_relationship_types)
			);
		}
		
		// Return the saved column info if possible
		if (!$relationship_type && isset($this->relationships[$table])) {
			return $this->relationships[$table];
		}
		
		if ($relationship_type && isset($this->relationships[$table][$relationship_type])) {
			return $this->relationships[$table][$relationship_type];
		}
		
		if (!in_array($table, $this->getTables())) {
			throw new fProgrammerException(
				'The table specified, %s, does not exist in the database',
				$table
			);
		}
		
		$this->fetchKeys();
		$this->mergeKeys();
		
		if ($relationship_type) {
			return $this->relationships[$table][$relationship_type];
		}
		
		return $this->relationships[$table];
	}
	
	
	/**
	 * Returns the tables in the current database
	 * 
	 * @param  boolean|string  $creation_order  `TRUE` to return in a valid table creation order, or a table name to return that table and any tables that depend on it, in table creation order
	 * @return array  The tables in the current database, all converted to lowercase
	 */
	public function getTables($creation_order=NULL)
	{
		if ($creation_order) {
			return $this->determineTableCreationOrder(is_bool($creation_order) ? NULL : $creation_order);
		}
		
		if ($this->tables !== NULL) {
			return $this->tables;
		}
		
		switch ($this->database->getType()) {
			case 'db2':
				$sql = "SELECT
							LOWER(RTRIM(TABSCHEMA)) AS \"schema\",
							LOWER(TABNAME) AS \"table\"
						FROM
							SYSCAT.TABLES
						WHERE
							TYPE = 'T' AND
							TABSCHEMA != 'SYSIBM' AND
							DEFINER != 'SYSIBM' AND
							TABSCHEMA != 'SYSTOOLS' AND
							DEFINER != 'SYSTOOLS'
						ORDER BY
							LOWER(TABNAME)";
				break;
				
			case 'mssql':
				$sql = "SELECT
							TABLE_SCHEMA AS \"schema\",
							TABLE_NAME AS \"table\"
						FROM
							INFORMATION_SCHEMA.TABLES
						WHERE
							TABLE_NAME != 'sysdiagrams'
						ORDER BY
							LOWER(TABLE_NAME)";
				break;
			
			case 'mysql':
				if (version_compare($this->database->getVersion(), 5, '<')) {
					$sql = 'SHOW TABLES';
				} else {
					$sql = "SHOW FULL TABLES WHERE table_type = 'BASE TABLE'";	
				}
				break;
			
			case 'oracle':
				$sql = "SELECT
							LOWER(OWNER) AS \"SCHEMA\",
							LOWER(TABLE_NAME) AS \"TABLE\"
						FROM
							ALL_TABLES
						WHERE
							OWNER NOT IN (
								'SYS',
								'SYSTEM',
								'OUTLN',
								'ANONYMOUS',
								'AURORA\$ORB\$UNAUTHENTICATED',
								'AWR_STAGE',
								'CSMIG',
								'CTXSYS',
								'DBSNMP',
								'DIP',
								'DMSYS',
								'DSSYS',
								'EXFSYS',
								'FLOWS_020100',
								'FLOWS_FILES',
								'LBACSYS',
								'MDSYS',
								'ORACLE_OCM',
								'ORDPLUGINS',
								'ORDSYS',
								'PERFSTAT',
								'TRACESVR',
								'TSMSYS',
								'XDB'
							) AND
							DROPPED = 'NO' 
						ORDER BY
							TABLE_NAME ASC";
				break;
			
			case 'postgresql':
				$sql = "SELECT
							 schemaname AS \"schema\",
							 tablename as \"table\"
						FROM
							 pg_tables
						WHERE
							 tablename !~ '^(pg|sql)_'
						ORDER BY
							LOWER(tablename)";
				break;
								
			case 'sqlite':
				$sql = "SELECT
							name
						FROM
							sqlite_master
						WHERE
							type = 'table' AND
							name NOT LIKE 'sqlite_%'
						ORDER BY
							name ASC";
				break;
		}
		
		$result = $this->database->query($sql);
		
		$this->tables = array();
		
		// For databases with schemas we only include the schema
		// name if there are conflicting table names
		if (!in_array($this->database->getType(), array('mysql', 'sqlite'))) {
			
			$default_schema_map = array(
				'db2'        => strtolower($this->database->getUsername()),
				'mssql'      => 'dbo',
				'oracle'     => strtolower($this->database->getUsername()),
				'postgresql' => 'public'
			);
			
			$default_schema = $default_schema_map[$this->database->getType()];
			
			foreach ($result as $row) {
				if ($row['schema'] == $default_schema) {
					$this->tables[] = strtolower($row['table']);	
				} else {
					$this->tables[] = strtolower($row['schema'] . '.' . $row['table']);	
				}
			}
				
		// SQLite and MySQL don't support schemas
		} else {
			foreach ($result as $row) {
				$keys = array_keys($row);
				$this->tables[] = strtolower($row[$keys[0]]);
			}
		}
		
		sort($this->tables);
		
		if ($this->cache) {
			$this->cache->set($this->makeCachePrefix() . 'tables', $this->tables);
		}
		
		return $this->tables;
	}
		
	
	/**
	 * Determines if a table is a joining table
	 * 
	 * @param  string $table  The table to check
	 * @return boolean  If the table is a joining table
	 */
	private function isJoiningTable($table)
	{
		$primary_key_columns = $this->merged_keys[$table]['primary'];
		
		if (sizeof($primary_key_columns) != 2) {
			return FALSE;	
		}
		
		if (empty($this->merged_column_info[$table])) {
			$this->getColumnInfo($table);	
		}
		if (sizeof($this->merged_column_info[$table]) != 2) {
			return FALSE;	
		}
		
		$foreign_key_columns = array();
		foreach ($this->merged_keys[$table]['foreign'] as $key) {
			$foreign_key_columns[] = $key['column'];
		}
		
		return sizeof($foreign_key_columns) == 2 && !array_diff($foreign_key_columns, $primary_key_columns);
	}
	
	
	/**
	 * Creates a unique cache prefix to help prevent cache conflicts
	 * 
	 * @return string  The cache prefix to use
	 */
	private function makeCachePrefix()
	{
		if (!$this->cache_prefix) {
			$prefix  = 'fSchema::' . $this->database->getType() . '::';
			if ($this->database->getHost()) {
				$prefix .= $this->database->getHost() . '::';
			}
			if ($this->database->getPort()) {
				$prefix .= $this->database->getPort() . '::';
			}
			$prefix .= $this->database->getDatabase() . '::';
			if ($this->database->getUsername()) {
				$prefix .= $this->database->getUsername() . '::';
			}
			$this->cache_prefix = $prefix;
		}
		
		return $this->cache_prefix;
	}
	
	
	/**
	 * Merges the column info with the column info override
	 * 
	 * @return void
	 */
	private function mergeColumnInfo()
	{
		$this->merged_column_info = $this->column_info;
		
		foreach ($this->column_info_override as $table => $columns) {
			// Remove a table if the columns are set to NULL
			if ($columns === NULL) {
				unset($this->merged_column_info[$table]);
				continue;	
			}
			
			if (!isset($this->merged_column_info[$table])) {
				$this->merged_column_info[$table] = array();
			}
			
			foreach ($columns as $column => $info) {
				// Remove a column if it is set to NULL
				if ($info === NULL) {
					unset($this->merged_column_info[$table][$column]);	
					continue;
				}
				
				if (!isset($this->merged_column_info[$table][$column])) {
					$this->merged_column_info[$table][$column] = array();
				}
				
				$this->merged_column_info[$table][$column] = array_merge($this->merged_column_info[$table][$column], $info);
			}
		}
		
		$optional_elements = array(
			'not_null',
			'default',
			'valid_values',
			'max_length',
			'max_value',
			'min_value',
			'decimal_places',
			'auto_increment',
			'comment'
		);
		
		foreach ($this->merged_column_info as $table => $column_array) {
			foreach ($column_array as $column => $info) {
				if (empty($info['type'])) {
					throw new fProgrammerException('The data type for the column %1$s is empty', $column);	
				}
				
				if (empty($this->merged_column_info[$table][$column]['placeholder'])) {
					$this->merged_column_info[$table][$column]['placeholder'] = strtr(
						$info['type'],
						array(
							'blob'      => '%l',
							'boolean'   => '%b',
							'date'      => '%d',
							'float'     => '%f',
							'integer'   => '%i',
							'char'      => '%s',
							'text'      => '%s',
							'varchar'   => '%s',
							'time'      => '%t',
							'timestamp' => '%p'
						)
					);
				}
				
				foreach ($optional_elements as $element) {
					if (!isset($this->merged_column_info[$table][$column][$element])) {
						$this->merged_column_info[$table][$column][$element] = ($element == 'auto_increment') ? FALSE : NULL;
					}
				}
			}
		}
		
		if ($this->cache) {
			$this->cache->set($this->makeCachePrefix() . 'merged_column_info', $this->merged_column_info);	
		}
	}
		
	
	/**
	 * Merges the keys with the keys override
	 * 
	 * @return void
	 */
	private function mergeKeys()
	{
		// Handle the database and override key info
		$this->merged_keys = $this->keys;
		
		foreach ($this->keys_override as $table => $info) {
			if (!isset($this->merged_keys[$table])) {
				$this->merged_keys[$table] = array();
			}
			$this->merged_keys[$table] = array_merge($this->merged_keys[$table], $info);
		}
		
		if ($this->cache) {
			$this->cache->set($this->makeCachePrefix() . 'merged_keys', $this->merged_keys);	
		}
		
		$this->findRelationships();
	}
	
	
	/**
	 * Allows overriding of column info
	 * 
	 * Performs an array merge with the column info detected from the database.
	 * 
	 * To erase a whole table, set the `$column_info` to `NULL`. To erase a
	 * column, set the `$column_info` for that column to `NULL`.
	 * 
	 * If the `$column_info` parameter is not `NULL`, it should be an
	 * associative array containing one or more of the following keys. Please
	 * see ::getColumnInfo() for a description of each.
	 *  - `'type'`
	 *  - `'placeholder'`
	 *  - `'not_null'`
	 *  - `'default'`
	 *  - `'valid_values'`
	 *  - `'max_length'`
	 *  - `'min_value'`
	 *  - `'max_value'`
	 *  - `'decimal_places'`
	 *  - `'auto_increment'`
	 *  - `'comment'`
	 * 
	 * The following keys may be set to `NULL`:
	 *  - `'not_null'`
	 *  - `'default'`
	 *  - `'valid_values'`
	 *  - `'max_length'`
	 *  - `'min_value'`
	 *  - `'max_value'`
	 *  - `'decimal_places'`
	 *  - `'comment'`
	 *  
	 * The key `'auto_increment'` should be a boolean.
	 * 
	 * The `'type'` key should be one of:
	 *  - `'blob'`
	 *  - `'boolean'`
	 *  - `'char'`
	 *  - `'date'`
	 *  - `'float'`
	 *  - `'integer'`
	 *  - `'text'`
	 *  - `'time'`
	 *  - `'timestamp'`
	 *  - `'varchar'`
	 * 
	 * @param  array  $column_info  The modified column info - see method description for format
	 * @param  string $table        The table to override
	 * @param  string $column       The column to override
	 * @return void
	 */
	public function setColumnInfoOverride($column_info, $table, $column=NULL)
	{
		$table = strotlower($table);
		if ($column !== NULL) {
			$column = strtolower($column);
		}

		if (!isset($this->column_info_override[$table])) {
			$this->column_info_override[$table] = array();
		}
		
		if (!empty($column)) {
			$this->column_info_override[$table][$column] = $column_info;
		} else {
			$this->column_info_override[$table] = $column_info;
		}
		
		$this->fetchColumnInfo($table);
		$this->mergeColumnInfo();
	}
	
	
	/**
	 * Allows overriding of key info. Replaces existing info, so be sure to provide full key info for type selected or all types.
	 * 
	 * @param  array  $keys      The modified keys - see ::getKeys() for format
	 * @param  string $table     The table to override
	 * @param  string $key_type  The key type to override: `'primary'`, `'foreign'`, `'unique'`
	 * @return void
	 */
	public function setKeysOverride($keys, $table, $key_type=NULL)
	{
		$table = strtolower($table);

		$valid_key_types = array('primary', 'foreign', 'unique');
		if (!in_array($key_type, $valid_key_types)) {
			throw new fProgrammerException(
				'The key type specified, %1$s, is invalid. Must be one of: %2$s.',
				$key_type,
				join(', ', $valid_key_types)
			);
		}
		
		if (!isset($this->keys_override[$table])) {
			$this->keys_override[$table] = array();
		}
		
		if (!empty($key_type)) {
			$this->keys_override[$table][$key_type] = $keys;
		} else {
			$this->keys_override[$table] = $keys;
		}
		
		$this->fetchKeys();
		$this->mergeKeys();
	}
}



/**
 * Copyright (c) 2007-2012 Will Bond <will@flourishlib.com>
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */