How to Connect PHP with MySQL Database




In this tutorial, we will learn how to connect PHP to a MySQL database.

In order to store or access the data inside a MySQL database, you first need to connect to the MySQL database server. PHP offers two different ways to connect to MySQL server: MySQLi (Improved MySQL) and PDO (PHP Data Objects) extensions.

Three Ways to Connecting to MySQL Database Server

First, you need to create a database in MySQL server:
create database test_db

1. Connect to MySQLi using Procedural way

<?php
/* Attempt MySQL server connection. Assuming you are running MySQL
server with default setting (user 'root' with no password) */

$host= "localhost";
$username= "root";
$password = "";

$db_name = "test_db";

// MySQLi, Procedural way
$mysql_connection = mysqli_connect($host, $username, $password, $db_name);

// Check connection
if($mysql_connection === false){
   die("ERROR: Could not connect. " . mysqli_connect_error());
}
 
// Print host information
echo "Connect Successfully. Host info: " . mysqli_get_host_info($mysql_connection);

// Close connection
mysqli_close($link);
?>

2. Connect to MySQLi using Object Oriented way

<?php
/* Attempt MySQL server connection. Assuming you are running MySQL
server with default setting (user 'root' with no password) */

$host= "localhost";
$username= "root";
$password = "";

$db_name = "test_db";

// MySQLi, Object Oriented way
$mysql_connection = new mysqli($host, $username, $password, $db_name);

// Check connection
if($mysql_connection === false){
    die("ERROR: Could not connect. " . mysqli_connect_error());
}
 
// Print host information
echo "Connect Successfully. Host info: " . mysqli_get_host_info($mysql_connection);

// Close connection
$mysql_connection->close();
?>

Note that we have created object:

// MySQLi, Object Oriented way
$mysql_connection = new mysqli($host, $username, $password, $db_name);

Close connection:

// Close connection
$mysql_connection->close();

3. Connect to MySQLi using PHP Data Objects (PDO) way

<?php
/* Attempt MySQL server connection. Assuming you are running MySQL
server with default setting (user 'root' with no password) */
try{
    $pdo = new PDO("mysql:host=localhost", "root", "");
    
    // Set the PDO error mode to exception
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    
    // Print host information
    echo "Connect Successfully. Host info: " . 
$pdo->getAttribute(constant("PDO::ATTR_CONNECTION_STATUS"));
} catch(PDOException $e){
    die("ERROR: Could not connect. " . $e->getMessage());
}
?>

// Close connection
unset($pdo);
Create object:
    $pdo = new PDO("mysql:host=localhost", "root", "");
Close connection:
// Close connection
unset($pdo);

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