Business Analyst: What is an entity-relationship diagram (ERD)?

ERD — visual representation of data entities and relationships.

Key elements:

• Entity — object or concept (e.g., Customer, Order).
• Attribute — property of entity (e.g., name, email).
• Relationship — connection between entities.

Example:

Cardinality:

• One-to-One (1:1): One customer, one profile.
• One-to-Many (1:N): One customer, many orders.
• Many-to-Many (M:N): Many students, many courses.

Benefits:

• Visualizes data structure.
• Supports database design.
• Identifies data requirements.