extmysql

Extmysql, commonly referred to as the MySQL extension for PHP, was a core PHP extension that provided a procedural interface for interacting with MySQL databases. It offered a set of functions such as mysql_connect, mysql_query, mysql_fetch_assoc, mysql_fetch_array, and mysql_close, enabling scripts to establish connections, send queries, and retrieve results. The extension relied on the libmysqlclient library to communicate with MySQL servers and did not provide object-oriented APIs or native prepared statement support.

Historically, extmysql was the default MySQL interface in early PHP versions, including PHP 4 and early PHP 5. As databases and PHP development evolved, the extension lagged behind in features and security practices, notably the lack of prepared statements and limited error handling. In response, the mysqli extension (and the PDO MySQL driver) were introduced, offering improved performance, support for prepared statements, enhanced error reporting, and an object-oriented interface.

Extmysql was deprecated in PHP 5.5.0 and removed entirely in PHP 7.0.0. Modern PHP environments no longer ship the extension, and legacy codebases using extmysql typically require migration to mysqli or PDO_MySQL. Migration generally involves updating function calls to their mysqli equivalents or reworking database access logic, potentially with adapters or compatibility layers.

See also: MySQL, PHP, mysqli, PDO_MySQL.