README.md

Sekwell

A basic formatter that uses FormattableString to automagically escape query arguments.

Use

Use the Statement class to dynamically build a SQL statement with interpolated arguments without fear of SQL injection.

Compile a Statement to create a DbCommand with the proper statement text and parameters, ready to execute using your preferred pattern, or call ToSql to get the raw statement and list of arguments passed in.

var name = "Shamus";
var stmt = new Statement($"SELECT * FROM Users")
    .Append($"WHERE FirstName={name}")

(string sql, object[] parms) = stmt.ToSql();
// sql = "SELECT * FROM Users WHERE FirstName=?"
// parms = {"Shamus"}

DbCommand cmd = stmt.Compile(connection);
// cmd.StatementText = "SELECT * FROM Users WHERE FirstName=?"
// cmd.Parameters[0] = DbParameter { Value = "Shamus" }

A statement's constructor only accepts a FormattableString as an argument to prevent accidental SQL injection. To pass in a raw string, you must explicitly use one of the functions with Raw in its name.

var name = "Shamus";
var query = $"SELECT * FROM Users WHERE NAME={name}"

// Will not compile!  `query` is a `string`, not `FormattableString`!
var stmt = new Statement(query);

// This will compile, but will be vulnerable to attacks. Use `Raw` sparingly!
var stmt = Statement.Raw(query);

For situations where you must manually create DbParameters (like "InOut" parameters), you can pass a parameter instance into the statement.

var param = new OdbcParameter("myParam", "");
using(var cmd = new Statement($"CALL SomeProcedure({param})").Compile(conn))
{
    await cmd.ExecuteNonQueryAsync();
}
// read param.Value

This package also provides various helper functions for easily quering domain objects in a System.Linq-style syntax.

var name = "Shamus";
User user = await conn.FirstOrDefaultAsync($"SELECT * FROM Users WHERE FirstName={name}",
    async reader =>
    {
        return new User
        {
            ID = (string)reader["ID"],
            FirstName = (string)reader["FirstName"],
            LastName = (string)reader["LastName"],
        };
    });