Can I Mix mysql_ and mysqli_ APIs in PHP, and How Can I Verify Connection Validity?

MySQL API Interoperability in PHP

Question:

It appears that mixing mysql_ and mysqli_ APIs in PHP is possible. However, when attempting to connect and close connections using a combination of these APIs, errors are encountered. Is it permissible to mix these APIs, and if not, how can the validity of connections be verified?

Answer:

Contrary to the initial assumption, mixing mysql_ and mysqli_ APIs in PHP is not advisable. These APIs are distinct, and the resources they generate are not interchangeable.

The following are the reasons why mixing MySQL APIs is problematic:

• Inconsistent Resource Types: mysql_ establishes connections as resources of type 'mysql', while mysqli_ creates resources of type 'mysqli'.
• API Call Compatibility: Functions related to connection setup and management, such as connection, closing, and error handling, differ between mysql_ and mysqli_.

The code snippets provided in the question demonstrate the issues that arise when mixing these APIs. The first code snippet utilizes both mysql_connect() and mysqli_connect_errno(), which results in a type mismatch error during connection closure. Similarly, the second snippet uses mysql_close() with an mysqli_ connection, also triggering an error.

Recommended Approach:

It is strongly recommended to use either the mysql_ API or the mysqli_ API for database connectivity. Avoid mixing the two APIs to prevent any potential compatibility issues or unexpected behavior.

Connection Validation:

To verify the validity of a database connection established using mysqli_, use the following code:

if (mysqli_connect_errno()) {
    // Handle connection error
}

This code checks if an error occurred during the connection establishment process and returns a non-zero value if an error is detected.

The above is the detailed content of Can I Mix mysql_ and mysqli_ APIs in PHP, and How Can I Verify Connection Validity?. For more information, please follow other related articles on the PHP Chinese website!