PHP Connect to MySQL

PHP Connect to MySQL Tutorial

PHP Connect to MySQL database is the first step for any dynamic web application. You can use mysqli (procedural or object-oriented) or PDO.

Using `mysqli` (Procedural)

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "test_db";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);

// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
echo "Connected successfully";
?>

<?php

$servername = "localhost";

$username = "root";

$password = "";

$dbname = "test_db";

// Create connection

$conn = mysqli_connect($servername, $username, $password, $dbname);

// Check connection

if (!$conn) {

die("Connection failed: " . mysqli_connect_error());

}

echo "Connected successfully";

$servername → Database host (usually localhost)
$username → MySQL username (default: root)
$password → MySQL password
$dbname → Name of your database

mysqli_connect_error() returns the error message if connection fails.

Using `mysqli` (Object-Oriented)

$conn->connect_error returns the connection error.
$conn object is used to execute queries later.

Using PDO (PHP Data Objects)

PDO provides flexible and secure database access and supports multiple databases.

<?php
try {
$conn = new PDO("mysql:host=localhost;dbname=test_db", "root", "");
// Set PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "Connected successfully";
} catch(PDOException $e) {
echo "Connection failed: " . $e->getMessage();
}
?>

<?php

try {

$conn = new PDO("mysql:host=localhost;dbname=test_db", "root", "");

// Set PDO error mode to exception

$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

echo "Connected successfully";

} catch(PDOException $e) {

echo "Connection failed: " . $e->getMessage();

}

PDO is preferred for prepared statements and database flexibility.

Closing the Connection

mysqli procedural:

mysqli object-oriented:

PDO: Automatically closed when $conn variable goes out of scope.

MySQLi vs PDO Comparison

MySQLi is simple and MySQL-only
PDO supports multiple databases
PDO supports named parameters
Both support prepared statements

For beginners, MySQLi is easier. For advanced projects, PDO is recommended.

Key Points

Check connection errors using mysqli_connect_error() or PDOException.
Use mysqli for MySQL-specific applications.
Use PDO for secure, flexible, and multi-database applications.
Always close the connection after finishing database operations.

PHP Connect to MySQL