Data Dictionary in Database

Data Dictionary in Database: The data dictionary is also referred as data repository or system catalog. It is an important part of DBMS. It contains data about data. It means that the data dictionary contains the actual database description managed by DBMS. Data dictionary is automatically updated as data is inserted and updated with the passage of time. The data dictionary contains the following information

• Logical structure of database such as table name, column name of each table and their data types and other properties, indices created in a table, and stored procedure name etc.
• Schemas, mapping and constraints.
• Description about application program.
• Description about physical database design such as storage structure, access path etc.
• Description about users of DBMS and their access rights.
• It also keeps record of accessing the database

Data Dictionary Format:

There are different types of data dictionaries. The main type of data dictionaries are described below.

• Integrated Data Dictionary
• Freestanding Data Dictionary