This document captures the detailed requirements of the database from the stakeholders. It includes business rules, data requirements, user needs, and specific functionalities that the database must support. Contents: User stories, data use cases, detailed data requirements, and any constraints or limitations.

An ERD is a visual representation of the database’s structure. It shows the entities, their attributes, and the relationships between these entities. Contents: Diagrams illustrating entities (tables), relationships (foreign keys), primary keys, and cardinality (one-to-one, one-to-many, many-to-many).

The schema definition includes the SQL scripts or database management system (DBMS) specific instructions to create the database structure. Contents: SQL scripts for creating tables, indexes, constraints (primary keys, foreign keys, unique constraints), and any other database objects like views, triggers, and stored procedures.