Classes with Object

Pre-requisites: Basic Understanding of Programming Language, MySQL.

In this project:

• We will create a class.
• The class will be composed of different methods to access data.
• These methods will be executed with the help of an object.

Type the following code in a PHP editor and save the file as UserClass.php in Classes folder of your root directory.

<?php
class User{
    		private $con;
    		public function connect($host, $user, $password, $database){
      		  	$this->con = mysqli_connect($host, $user, $password, $database);
        		if (mysqli_connect_errno()) {
            			echo "Connection Failed __".mysqli_connect_error();
            			exit();     
        		}	
    		}
    		public function getEmployeeData(){
        		$arr = $mainArr = array();
        		$sql = "SELECT a.first_name, a.last_name, a.email_id, b.name 
                    		FROM employees a 
                    		LEFT JOIN department b ON a.department_id = b.id 
                    		WHERE b.id IS NOT NULL";
        		$result = mysqli_query($this->con, $sql);
        		if($result){
            			while($row = mysqli_fetch_assoc($result)){
            		    		$arr['first_name'] = $row['first_name'];
                			$arr['last_name'] = $row['last_name'];
                			$arr['email_id'] = $row['email_id'];
                			$arr['name'] = $row['name'];
                			$mainArr[] = $arr;
            			}
        		}        
        		return $mainArr;
    		}    
}
$userObj = new User;
$userObj->connect("localhost", "root", "", "testing"); 
$employeeData = $userObj->getEmployeeData();
echo "<table border='1' cellpadding='5' cellspacing='0'>
                	<tr>
                   	<th>First Name</th>
                    	<th>Last Name</th>
                    	<th>Email ID</th>
                    	<th>Department</th>
                  </tr>";
if(is_array($employeeData) && count($employeeData) > 0){
    		
    		foreach($employeeData as $innerArr){
        		echo "<tr>";
        		foreach($innerArr as $key => $val){
            			echo "<td>".$val."</td>"; 
        		}
        		echo "</tr>";
    		}    		
}else{
    		echo "<tr>
            			<td colspan='4'>No records found</td>
        		</tr>";
}
echo "</table>";
?>

Run UserClass.php file in your browser to get the following output. URL may look like as follows:

class User{

…     

}

private $con;

public function connect($host, $user, $password, $database){

…   

}

$this->con=mysqli_connect($host,$user,$password,$database);

public function getEmployeeData(){

…

}

while($row = mysqli_fetch_assoc($result)){

     $arr['first_name'] = $row['first_name'];

     $arr['last_name'] = $row['last_name'];

     $arr['email_id'] = $row['email_id'];

     $arr['name'] = $row['name'];

     $mainArr[] = $arr;

}

$userObj = new User;

$userObj->connect("localhost", "root", "", "testing"); 

$employeeData = $userObj->getEmployeeData();

foreach($employeeData as $innerArr){

   echo "<tr>";

   foreach($innerArr as $key => $val){

      echo "<td>".$val."</td>"; 

   }

   echo "</tr>";

}

Summary

In this project, we have learned to create a Class, declaring variables, defining public member functions of the class, object creation and calling methods outside the class with the help of objects.

Two methods are taken where first method, connect() is defined to connect to a database and second method, getEmployeeData() is defined to retrieve the records from employees table along with their department name.

If records exist, it is printed on screen in the form of table. Otherwise, ‘No Records found’ message is printed.