function.php

<?php
	session_start();
	define('DB_SERVER', 'localhost');
	define('DB_USER', 'root');
	define('DB_PASS', 'password');
	define('DB_NAME', 'oopscrud');
	
	class DB_con
	{
		function __construct()
		{
			$con = mysqli_connect(DB_SERVER, DB_USER, DB_PASS, DB_NAME);
			$this->dbh = $con;

			// Check connection
			if (mysqli_connect_errno()) {
				echo "Failed to connect to MySQL: " . mysqli_connect_error();
			}
		}

		//Data Insertion Function
		public function insert($fname, $lname, $emailid, $contactno, $address)
		{
			$ret = mysqli_query($this->dbh, "insert into tblusers(FirstName,LastName,EmailId,ContactNumber,Address) values('$fname','$lname','$emailid','$contactno','$address')");
			return $ret;
		}

		//Data read Function
		public function fetchdata()
		{
			$result = mysqli_query($this->dbh, "select * from tblusers");
			return $result;
		}

		//Data one record read Function
		public function fetchonerecord($userid)
		{
			$oneresult = mysqli_query($this->dbh, "select * from tblusers where id=$userid");
			return $oneresult;
		}

		//Data updation Function
		public function update($fname, $lname, $emailid, $contactno, $address, $userid)
		{
			$updaterecord = mysqli_query($this->dbh, "update  tblusers set FirstName='$fname',LastName='$lname',EmailId='$emailid',ContactNumber='$contactno',Address='$address' where id='$userid' ");
			return $updaterecord;
		}
		
		//Data Deletion function Function
		public function delete($rid)
		{
			$deleterecord = mysqli_query($this->dbh, "delete from tblusers where id=$rid");
			return $deleterecord;
		}
	}