(PHP 5, PHP 7) Pings a server connection, or tries to reconnect if the connection has gone down

(PHP 5, PHP 7) Returns the MySQL client version as an integer

(PHP 5 >= 5.0.5, PHP 7) Sets the default client character set

(PHP 5, PHP 7) Selects the default database for database queries

(PHP 5 >= 5.5.0, PHP 7) Starts a transaction

(PHP 5, PHP 7) Turns on or off auto-committing database modifications

(PHP 5, PHP 7) Returns the version of the MySQL server

(PHP 5, PHP 7) Changes the user of the specified database connection

(PHP 5 >= 5.5.0, PHP 7) Set a named transaction savepoint

(PHP 5, PHP 7) Unsets user defined handler for load local infile command