MySQL has advanced database access system. A database user can have access to the whole database, separate tables, or to separate columns of tables. Also there is a restriction for actions a user may perform with records. MySQL server uses several tables in a special database to organize such a complicated database access structure. The access policy is based on the values available in these tables.
The database that MySQL server uses to store internal data about users is called mysql by default. There are tables for storing information about users’ accounts in this database: