Definition
Data Dictionary
A centralized repository that stores metadata about the data in a database.
- To be more specific, a data dictionary acts as a reference guide for database administrators, developers, and users.
- It does this by providing essential information about the structure, constraints, and relationships within the database.
Note
- The data dictionary does not store the actual data but describes the data stored in the database.
Key Components of a Data Dictionary
- Table Names: The names of all tables in the database.
- Field Names: The names of all fields (columns) within each table.
- Data Types: The type of data stored in each field (e.g., integer, string, date).
- Field Sizes: The maximum length or size of data that can be stored in each field.
- Constraints: Rules applied to fields, such as primary keys, foreign keys, unique constraints, and default values
- Relationships: Links between tables, such as one-to-many or many-to-many relationships.
- Indexes: Indexes created to improve query performance.
- Descriptions: Human-readable explanations of fields and tables.
