Each table in the database has a table ID of a fixed length, which gives the table a unique identity.
The database system uses the table ID to access a table. When a table is accessed externally, for example by an SQL statement, it is addressed using its table name. The allocation of the table name to the table ID is stored in the database catalog; the allocation of the table ID to the B* trees is stored in the file directory.
See also:
Concepts of the Database System, Data Storage in B* Trees