ERD - Entity Relationship Diagram

Entity Relationship Diagrams (ERDs) contain a wealth of information on the architecture of a relational database. An entity relationship diagram at best can only be considered a static picture of the structure of a database. Nothing is revealed regarding the flow of data, or anything else that relates to how the data changes. However, exploring an entity relationship diagram is often a first step in understanding a database’s design. Data models are tools used in analysis to describe the data requirements and assumptions in the system from a top-down perspective.

There are three basic elements in ER models:

Entities are those things about which we seek information.
Attributes are the data we collect about the entities.
Relationships provide the structure needed to draw information from multiple entities.

The ERD brings out:

Many-to-many relationships
Ambiguities
Entities and their relationships
What data needs to be stored
The degree of a relationship

Reading the ERD

Open the issue entity relationship diagram to get to know the table name and its relationship with other tables in the database. Refer to the DDF file for a list of all the views that the table is associated with, and select the view that provides the maximum information.

The name of the ERD file: ERActor.pdf

From the ERD file you can conclude that ACT_ACTOR is the name of the Actor entity. The table has relationship with Roles, Rights Group, Organization, Organization Unit and other tables.

Pilgrim provides an ERD file for each entity. Review and verify other ERD files until a proper relationship is established.