Data Dictionaries in Relational Databases: Metadata Management and Organization

Understand the importance of data dictionaries in relational database management. This guide explains their role in storing metadata about database objects (tables, columns, etc.), relationships, and other key characteristics, enhancing database understanding and facilitating efficient database administration.

Data Dictionaries in Relational Databases

What is a Data Dictionary?

A data dictionary is a structured repository of metadata about a database. It contains information about the database's objects (tables, columns, etc.), their relationships, and other key characteristics. While essential for database management, the data dictionary itself is usually not directly accessed by typical database users; database administrators primarily manage the data dictionary.

Information Contained in a Data Dictionary

A data dictionary typically includes information about each data item in the database. This metadata helps in understanding the data's structure and purpose.

• Name: The name of the data item.
• Aliases: Alternative names for the data item.
• Description/Purpose: A textual description of the data item's use.
• Related Data Items: Relationships between data items (e.g., constraints or dependencies).
• Range of Values: The allowed values for the data item.
• Data Structure Definition/Forms: The data type and structure of the data item (primitive data types, or how a complex data type is structured using other data types).
• Data Flows: The processes that use the data item.

Mathematical Operators Used in Data Dictionaries