Can I Simply Replace `mysql_` with `mysqli_` in My PHP Code?

Blindly Replacing mysql_ with mysqli_: A Cautionary Tale

The obsolescence and eventual removal of mysql_ functions from PHP has prompted the question: can they be seamlessly replaced with mysqli_? While it may be tempting to assume equivalence, the answer is a resounding no.

Converter Tool: A Temporary Solution

Thankfully, for those with extensive existing code using mysql_ functions, there exists a converter tool (https://github.com/philip/MySQLConverterTool) that can automate most of the conversion process. This can provide immediate functionality, allowing scripts to execute as expected.

Manual Migration: Embracing Object Orientation

Beyond the temporary solution offered by the converter tool, it's prudent to migrate to an object-oriented methodology for database interaction. This approach offers several advantages, including improved code organization and maintainability.

1. Connection Establishment

In mysqli_, establishing a connection involves creating a new mysqli object and assigning it to a PHP variable. For example:

$mysqli = new mysqli($host, $username, $password, $database);

Make sure to enable error reporting for mysqli_ before opening the connection:

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

2. Query Execution

All mysqli_ functions now require the connection as the first argument in procedural code or as an object method in object-oriented code. For executing a query, the code would look like this:

Procedural:

$result = mysqli_query($mysqli, $sql);

Object-oriented:

$result = $mysqli->query($sql);

3. Result Fetching

Result fetching remains largely unchanged in mysqli_ from its mysql_ counterpart.

Procedural:

while ($row = mysqli_fetch_assoc($result))

Object-oriented:

while ($row = $result->fetch_assoc())

4. Connection Closure

Properly closing the connection is essential, and the process remains consistent with mysql_ in mysqli_:

Procedural:

mysqli_close($mysqli);

Object-oriented:

$mysqli->close();

Additional Considerations

The migration from mysql_ to mysqli_ involves converting all related functions, including those for connection close, result release, error handling, and row counting.

Remember, while the initial conversion may require some manual labor, embracing the object-oriented approach can yield long-term benefits for your codebase. So, while blindly replacing mysql_ functions with mysqli_ is not an ideal solution, it can be a stepping stone towards a more modern and maintainable PHP codebase.

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