Lesson 8 : - Database Connectivity in PHP?

💡 What is Database Connectivity in PHP?

Database connectivity means connecting your PHP script with a database (like MySQL) to perform actions like Insert, Retrieve, Update, or Delete data using SQL.

PHP offers two main methods to connect with databases:

• MySQLi (MySQL Improved)
• PDO (PHP Data Objects)

---

✅ Database Connection using MySQLi (Procedural)

🔹 Step 1: Set Database Credentials

<?php
$servername = "localhost";
$username = "root";
$password = "";
$database = "my_database";

🔹 Step 2: Create Connection

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

🔹 Step 3: Check Connection

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

✅ Full Working Example

<?php
$servername = "localhost";
$username = "root";
$password = "";
$database = "my_database";

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

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

---

✅ Database Connection using PDO

<?php
$servername = "localhost";
$username = "root";
$password = "";
$database = "my_database";

try {
    // Create PDO connection
    $conn = new PDO("mysql:host=$servername;dbname=$database", $username, $password);

    // 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();
}
?>

---

📊 Comparison Table

Method	Description	Best Use
MySQLi	Works with MySQL only	Best for beginners and local projects
PDO	Works with multiple DB types	Best for advanced and secure apps

---

📌 What Can You Do After Connecting?

• INSERT data using SQL
• SELECT data to view records
• UPDATE data when needed
• DELETE unwanted data