What is theuse of data dictionary in RDBMS?

Answer 1

The term Data Dictionary and Data Repository are used to indicate a more general software utility than a catalogue. A Catalogue is closely coupled with the DBMS Software; it provides the information stored in it to user and the DBA, but it is mainly accessed by the various software modules of the DBMS itself, such as DDL and DML compilers, the query optimiser, the transaction processor, report generators, and the constraint enforcer. On the other hand, a Data Dictionary is a data structure that stores meta-data, i.e., data about data. The Software package for a stand-alone Data Dictionary or Data Repository may interact with the software modules of the DBMS, but it is mainly used by the Designers, Users and Administrators of a computer system for information resource management. These systems are used to maintain information on system hardware and software configuration, documentation, application and users as well as other information relevant to system administration

Answer 2

A data dictionary in a relational database management system (RDBMS) is used to store metadata information about the database, including the structure of tables, data types, relationships between tables, constraints, and other database objects. It provides a centralized repository for managing and documenting database schema information, which can help in data modeling, database design, development, and maintenance processes. It also helps ensure data consistency and integrity by serving as a reference for database users, administrators, and developers.