What is an Entity Relationship Diagram?
An entity relationship diagram describes how entities relate to each other. In simple terms, it’s a picture or a framework of your business or a certain business process. (Learn more about business process modeling). Entities are the things we need to store data about. It’s an aspect of your business that needs to store data, such as a department – or sales, revenues, maybe clients, for example. See an example:
Visualizing your business
Each branch of the business, or entity, may be related to another entity or to many entities, and vice versa. There are three main types of relationships: one-to-one (1:1), one-to-many and many-to-many.- You could try imagining a one-to-one relationship as a manager’s relationship with their department.
- A one-to-many relationship could be the department’s relationship to its (many) employees.
- Think of a many-to-many relationship in this way: the relationships between many employees and the projects they’re involved with. In business analytics, a query against a many-to-many relationship can produce problematic results.
