A connection resource handle. An integer returned from the functions mysql_connect( ) , and mysql_pconnect( ) . Both functions are used to establish a connection to a MySQL DBMS, and are described later in this chapter. The connection resource handle is used as a parameter to several functions (such as mysql_select_db( ) , mysql_query( ), and mysql_affected_rows( ) ) to determine or change aspects of the connection.

A query resource handle. An integer returned from functions such as mysql_query() , mysql_list_fields() , mysql_list_dbs() , and mysql_unbuffered_query() . These functions are used to execute a query through a connection resource handle, and are described later in this chapter. A query resource handle is used as a parameter to several functions (such as mysql_fetch_array() , mysql_tablename() , and mysql_num_rows() ) to retrieve a query’s output or information about the query.