class created to handle sql queries to a database

gistfile1.txt

<?php

	
class GeneralDAL {
	
	// Instance variable
	private $con = null;
	private $tableName = '';
	
	function __construct($url,$userid,$password,$databaseName, $tableName) {
	
		$this->tableName = $tableName;
		if ($this->con == null) {
			$this->con=mysqli_connect($url,$userid,$password,$databaseName);	
		}
		
		if (mysqli_connect_errno()) {
		echo "Failed to connect to MySQL: " . mysqli_connect_error();
		}
		
	}

	
	function __destruct() {
		
		if ($this->con != null) {
			mysqli_close($this->con);
			//print "Destroying 3\n";
		}
	
	}

	function update($columns) {
	
		
		$allcolumns = "";
		$key = "";
		$comma = "";
		foreach($columns as $x=>$x_value)
		{
			if($x == 'id')
			{
				$key = $key . $x . "='$x_value'";
			} else {
				$allcolumns = "$allcolumns $comma $x = '$x_value'";
				$comma = ", ";
			}
		} 
		 $updateSQL = "UPDATE $this->tableName SET $allcolumns WHERE $key";
		
		
		mysqli_query($this->con,$updateSQL);
	}
	
	function delete($key) {
		
		 mysqli_query($this->con,"DELETE FROM $this->tableName WHERE id = $key");
		echo "test2";
	}
	
	function insert($columns) {
		
		$allColumns = "";
		$allValues = "";
		$comma = "";
	
		foreach($columns as $x=>$x_value)
		{
			$allColumns = $allColumns . $comma . $x ;
			$comma = ", ";	
		}
	
		$comma = "";
		foreach($columns as $x=>$x_value)
		{
			$allValues = $allValues . $comma . "'$x_value'" ;
			$comma = ", ";
		
		}
	
		$insertSQL = " INSERT INTO $this->tableName ($allColumns) VALUES ($allValues) ";

		mysqli_query($this->con, $insertSQL);

	
	}
	function select($sql){
		$result = mysqli_query($this->con, $sql);
		$resultData = [];
		while($row = mysqli_fetch_array($result))
		{
		  array_push( $resultData,$row);
		}
		return $resultData;
	}

}



?>