PHP Connect to MySQL

🔗 PHP Connect to MySQL Tutorial

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

1️⃣ 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.

2️⃣ Using `mysqli` (Object-Oriented)

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

3️⃣ 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.

4️⃣ Closing the Connection

mysqli procedural:

mysqli object-oriented:

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

5️⃣ 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