How to Connect Database in PHP? Using MySQL and PDO

To connect database in PHP, you will need to use the MySQLi (MySQL Improved) or PDO (PHP Data Objects) extension. Both of these extensions provide an object-oriented interface for interacting with a MySQL database.

Connect Database in PHP:

Here is an example of how to connect to a MySQL database using the MySQLi extension:

<?php
$servername = "hostname";
$username = "username";
$password = "password";
$dbname = "database name";

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

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

Here is an example of how to connect to a MySQL database using the PDO extension:

<?php
$servername = "hostname";
$username = "username";
$password = "password";
$dbname = "database name";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully"; 
    }
catch(PDOException $e)
    {
    echo "Connection failed: " . $e->getMessage();
    }
?>

Please make sure to replace the placeholders (hostname, username, password, and database name) with the appropriate values for your database. It’s important to also make sure that you have the correct driver installed to connect to the database.

It is also good practice to close the database connection after you have finished interacting with the database, to free up resources and prevent any unwanted access. You can close the connection by calling $conn->close() (MySQLi) or $conn = null (PDO).

Read More : How to Generate QR code in Laravel App

When connecting to a database in PHP, it is important to consider security best practices. One such practice is to use prepared statements to prevent SQL injection attacks. Prepared statements allow you to separate the data from the query, which can help protect against malicious input.

Here’s an example of how to use a prepared statement with the MySQLi extension:

<?php
$servername = "hostname";
$username = "username";
$password = "password";
$dbname = "database name";

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

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$stmt = $conn->prepare("INSERT INTO table_name (column1, column2, column3) VALUES (?, ?, ?)");
$stmt->bind_param("sss", $value1, $value2, $value3);

// set parameters and execute
$value1 = "example1";
$value2 = "example2";
$value3 = "example3";
$stmt->execute();

echo "New records created successfully";

$stmt->close();
$conn->close();
?>

And here is how to use a prepared statement with the PDO extension:

<?php
$servername = "hostname";
$username = "username";
$password = "password";
$dbname = "database name";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $stmt = $conn->prepare("INSERT INTO table_name (column1, column2, column3) VALUES (:value1, :value2, :value3)");
    $stmt->bindParam(':value1', $value1);
    $stmt->bindParam(':value2', $value2);
    $stmt->bindParam(':value3', $value3);
    
    // insert a row
    $value1 = "example1";
    $value2 = "example2";
    $value3 = "example3";
    $stmt->execute();
    
    echo "New records created successfully";
    }
catch(PDOException $e)
    {
    echo "Error: " . $e->getMessage();
    }
$conn = null;
?>

It is also a good practice to use parameterized queries to prevent SQL injection attacks. It’s also recommended to use a secure connection such as SSL or TLS when connecting to the database, to protect sensitive data.

Please keep in mind that this is just a sample code, you should adjust to your specific requirements and test the code before using it in production.