How can I rewrite legacy PHP code using deprecated `mysql_*` functions?

Rewriting Legacy PHP Code with Deprecated mysql_* Functions

As you've discovered, mysql_* functions in PHP have been deprecated due to security and stability concerns. To effectively rewrite your code, consider the following guidelines:

1. Switch to PDO or Prepared Statements:

Replace mysql_* functions with PDO or prepared statements to improve security and avoid SQL injection vulnerabilities.

2. Reconfigure Database Connection:

The database connection should be established using a connection string instead of individual parameters. For example:

<code class="php">$db = new PDO('mysql:host=127.0.0.1;dbname=people;charset=UTF-8', 'root', 'pass');</code>

3. Remove Unnecessary Constructor and Destructor:

Functions like __construct and __destruct are no longer necessary with PDO. PDO handles database connection and cleanup internally.

4. Simplified Database Selection:

To select a database with PDO, use the exec method:

<code class="php">$db->exec("USE " . $database);</code>

5. Consider Database Class Extension:

If desired, you can extend from PDO to create your own database class with custom functionality.

Example Rewrite:

Your original script can be rewritten as follows using PDO:

<code class="php">class dbConn extends PDO
{
    public function connect()
    {
        try {
            parent::__construct('mysql:host=127.0.0.1;dbname=people;charset=UTF-8', 'root', 'pass');
        } catch (PDOException $e) {
            die('Database connection failed: ' . $e->getMessage());
        }
    }

    public function selectDb($database)
    {
        $this->exec("USE " . $database);
        $this->query("SET NAMES 'utf8'");
    }
}</code>

Remember, switching to PDO or prepared statements not only enhances security but also simplifies code maintenance and improves performance.

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