A database about data and databases. A data dictionary holds the name, type, range of values, source and authorization for access for each data element in the organization's files and databases. It also indicates which application programs use that data so that when a change in a data structure is contemplated, a list of affected programs can be generated.
The data dictionary may be a stand-alone system or an integral part of the DBMS. Data integrity and accuracy is better ensured in the latter case. See DBMS
and data administration