A data dictionary is a file or a set of files that contains a database’s metadata. The data dictionary contains records about other objects in the database, such as data ownership, data relationships to other objects, and other data.
The data dictionary is a crucial component of any relational database. It provides additional information about relationships between different database tables, helps to organize data in a neat and easily searchable way, and prevents data redundancy issues.
Ironically, because of its importance, it is invisible to most database users. Typically, only database administrators interact with the data dictionary
