As of PHP 5.5, the original MySQL extension has been deprecated and removed from PHP 7.0 onwards. This means that it's time to update your code and switch to the more modern and secure MySQLi or PDO extensions. In this guide, we'll walk you through the steps for migrating your code and discuss the benefits of using MySQLi or PDO.
Table of Contents
Understanding MySQLi and PDO
Before we dive into the migration process, let's take a moment to understand the differences between the deprecated MySQL extension and the newer MySQLi and PDO extensions:
- MySQLi (MySQL Improved) is an extension that provides an object-oriented and procedural interface for working with MySQL databases. It supports prepared statements, transactions, and multiple statements. Learn more about MySQLi.
- PDO (PHP Data Objects) is a database access layer that provides a consistent interface for working with various databases, including MySQL. It supports prepared statements and transactions, making it a more versatile choice if you plan to work with different databases in the future. Learn more about PDO.
Migrating to MySQLi
Migrating your code from the deprecated MySQL extension to MySQLi involves updating your connection, query, and fetching functions. Here's a step-by-step guide:
Update your connection function. Replace mysql_connect and mysql_select_db with mysqli_connect:
// Old code
$link = mysql_connect('localhost', 'username', 'password');
mysql_select_db('database_name', $link);
// New code
$link = mysqli_connect('localhost', 'username', 'password', 'database_name');
Update your query function. Replace mysql_query with mysqli_query:
// Old code
$result = mysql_query('SELECT * FROM table_name', $link);
// New code
$result = mysqli_query($link, 'SELECT * FROM table_name');
Update your fetching functions. Replace mysql_fetch_array, mysql_fetch_row, and mysql_fetch_assoc with their MySQLi equivalents:
// Old code
while ($row = mysql_fetch_assoc($result)) {
// Do something with $row
}
// New code
while ($row = mysqli_fetch_assoc($result)) {
// Do something with $row
}
Migrating to PDO
Migrating your code from the deprecated MySQL extension to PDO involves updating your connection, query, and fetching functions. Here's a step-by-step guide:
Update your connection function. Replace mysql_connect and mysql_select_db with a PDO object:
// Old code
$link = mysql_connect('localhost', 'username', 'password');
mysql_select_db('database_name', $link);
// New code
$pdo = new PDO('mysql:host=localhost;dbname=database_name', 'username', 'password');
Update your query function. Replace mysql_query with PDO::query:
// Old code
$result = mysql_query('SELECT * FROM table_name', $link);
// New code
$result = $pdo->query('SELECT * FROM table_name');
Update your fetching functions. Replace mysql_fetch_array, mysql_fetch_row, and mysql_fetch_assoc with their PDO equivalents:
// Old code
while ($row = mysql_fetch_assoc($result)) {
// Do something with $row
}
// New code
foreach ($result as $row) {
// Do something with $row
}
FAQ
1. What are the main differences between MySQLi and PDO?
MySQLi is specific to MySQL databases, while PDO supports multiple databases. Both extensions support prepared statements and transactions, but MySQLi also supports multiple statements. PDO is generally considered more flexible due to its consistent interface for working with various databases.
2. Is it possible to use both MySQLi and PDO in the same project?
Yes, it is possible to use both MySQLi and PDO in the same project. However, it is best to choose one and stick to it for consistency.
3. Can I use MySQLi or PDO with other databases like PostgreSQL or SQLite?
PDO supports multiple databases, including PostgreSQL and SQLite. MySQLi, however, is specific to MySQL databases.
4. How do I handle errors in MySQLi and PDO?
Both MySQLi and PDO have built-in error handling mechanisms. By default, PDO will throw exceptions, while MySQLi will return error codes. You can customize error handling by using mysqli_report() in MySQLi and PDO::setAttribute() in PDO.
5. How do I migrate my existing MySQL code to use prepared statements with MySQLi or PDO?
To use prepared statements with MySQLi or PDO, you need to update your code to use the mysqli_prepare() or PDO::prepare() functions, respectively. See the MySQLi prepared statements documentation and the PDO prepared statements documentation for detailed examples.