Business Analyst: What is a data dictionary in database?

Data dictionary — metadata about database objects.

Contents:

• Table definitions.
• Column names and types.
• Constraints.
• Indexes.
• Relationships.

Example:

1-- View table structure
2DESCRIBE customers;
3
4-- MySQL
5SHOW COLUMNS FROM customers;
6
7-- PostgreSQL
8SELECT column_name, data_type
9FROM information_schema.columns
10WHERE table_name = 'customers';

Benefits:

• Understand data structure.
• Support development.
• Documentation.

BA use:

• Validate data requirements.
• Write specifications.
• Communicate with developers.