MySQL in a Nutshell, 2nd Edition

Name

mysql_change_user()

Synopsis

my_bool mysql_change_user(MYSQL *mysql, const char *user, 
                          const char *password, const char *database)

Use this function to change the current user for the MySQL session to the one given as the second argument. The password of the new user is given in the third argument. Since this function will end the current session if successful, it will need to reset the default database. Therefore, a database that it should use for the new connection is to be given as the fourth argument. Here is an example:

...
mysql_real_connect(mysql,"localhost","hui","shorty","test","3306",NULL,0);
mysql_select_db(mysql,"workrequests");
...
mysql_change_user(mysql,"russell","password","workrequests");
mysql_query(mysql, "UPDATE workreq
                    SET tech_person_id = '1015'
                    WHERE tech_person_id = '1012'");
...

In this example, the program begins with one user for running SQL statements, which are replaced with ellipses. However, for changing a sensitive data column (i.e., the person assigned to perform the work requests), the user is changed to one who has been given the proper authorization to access.