How to Effectively Migrate from MySQL to MySQLi Syntax?

Updating MySQL to MySQLi Syntax

Question:

Can you migrate MySQL functions to mysqli syntax by replacing mysql_query($sql) with mysqli_query($sql)?

Answer:

While replacing MySQL functions with mysqli equivalents seems like a straightforward approach, it requires a more comprehensive update.

Detailed Conversion Process:

1. Search and Replace: Replace all mysql_* function calls with their mysqli_* counterparts, as seen in the Function Summary for the MySQLi Extension.

   • mysql_connect → mysqli_connect
   • mysql_error → mysqli_error/mysqli_connect_error (depending on context)
   • mysql_query → mysqli_query

2. Database Selection:

   • MySQL: Involves using mysql_select_db after connecting.
   • MySQLi: Database name can be specified as the fourth parameter in mysqli_connect. Alternatively, mysqli_select_db can still be used.

3. Additional Considerations:

   • Check parameter differences between similar functions in MySQL and MySQLi.
   • Execute the updated script and troubleshoot any errors that arise.

Example:

Original MySQL code:

$sql = 'SELECT auto_id FROM friend_reg_user WHERE auto_id=' . $info['auto_id'];
$result_member = executequery($sql);
if ($line_member = mysql_fetch_array($result_member)) {
    extract($line_member);
} else {
    header("location: index.php");
    exit;
}

Updated MySQLi code:

$sql = 'SELECT auto_id FROM friend_reg_user WHERE auto_id=' . $info['auto_id'];
$result_member = mysqli_query($conn, $sql);
if ($line_member = mysqli_fetch_array($result_member)) {
    extract($line_member);
} else {
    header("location: index.php");
    exit;
}

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