Can I Directly Swap All `mysql_` Functions with `mysqli_` Functions in PHP?

Can I Replace All mysql_ Functions with mysqli_?

Introduction
As PHP 5.5 deprecated the mysql_ functions and removed them in PHP 7, developers need to migrate to alternative functions. One common question is whether we can blindly replace all mysql_ functions with mysqli_.

Answer
No, the mysql_ and mysqli_ functions are not equivalent. While some basic functions like mysql_query() and mysqli_query() have similar functionality, there are significant differences in syntax, parameter order, and object-oriented approach.

MySQLConverterTool
Thankfully, there is a converter tool that can assist in this migration. The MySQLConverterTool (https://github.com/philip/MySQLConverterTool) can automatically convert mysql_ function calls to their mysqli_ equivalents, enabling scripts to work immediately.

Manual Migration
Alternatively, manual migration involves the following steps:

1. Connection
Create a new connection function using mysqli_connect(), replacing mysql_connect(). Store the connection in a variable like $mysqli.

2. Query
Include the connection in your query functions. In procedural code, it's the first argument (e.g., mysqli_query($mysqli, $sql)). In OO, use the class method (e.g., $mysqli->query($sql)).

3. Fetch Result
Use either mysqli_fetch_assoc() (procedural) or $result->fetch_assoc() (OO) to retrieve results.

4. Close Connection
Close the connection using mysqli_close() (procedural) or $mysqli->close() (OO).

Conclusion
While it's tempting to replace mysql_ with mysqli_ blindly, it's crucial to consider the differences and migrate manually or use the converter tool to avoid adverse effects. By following these steps, you can ensure a successful transition to using mysqli_.

The above is the detailed content of Can I Directly Swap All `mysql_` Functions with `mysqli_` Functions in PHP?. For more information, please follow other related articles on the PHP Chinese website!