What is an ER Diagram?
ER Diagram stands for Entity Relationship Diagram, also known as ERD, is a diagram that shows the relationship of sets of assets stored in a database. In other words, ER diagrams help explain the logical structure of databases. ER diagrams are built around three key concepts: entities, attributes, and relationships.
ER Diagrams contain different symbols that use rectangles to represent entities, ovals to describe attributes, and diamond shapes to represent relationships.
The purpose of the ER Diagram is to represent the entity framework infrastructure.
What is the ER Model?
ER Model stands for Entity Relationship Model, it is a high level conceptual data model diagram. The ER model helps to systematically analyze data requirements to build a well-designed database. The ER Model represents real-world entities and the relationships between them. Creating an ER Model in DBMS is considered best practice before implementing your database.
ER Modeling helps you systematically analyze data requirements to build a well-designed database. Therefore, it is considered best practice to complete the ER modeling before implementing your database.
How to Create an ER Diagram (ERD)
Best Practices for Developing Effective ER Diagrams
History of ER models
ER diagrams are a visual tool to help represent the ER model. It was proposed by Peter Chen in 1971 to create a uniform convention that could be used for relational database and networking. It aimed to use an ER model as a conceptual modeling approach.
Why use ER Diagrams?
Here are the main reasons to use the ER Diagram
Helps you define terms related to entity relationship modeling
Provide a preview of how all your tables should be linked, what fields will be in each table
Helps to identify entities, attributes, relationships
ER diagrams can be translated into relational tables allowing you to quickly build databases
ER diagrams can be used by database designers as a blueprint for implementing data in specific software applications
With the help of the ERP diagram, the database designer better understands the information that should be included in the database.
ERD Diagram allows you to communicate with users with the logical structure of the database
Facts about the ER Diagram Model
Now in this ERD Diagram Tutorial, let’s explore some interesting facts about the ER Diagram Pattern:
ER model lets you draw Database Design
An easy-to-use graphical tool for modeling data
Widely used in Database Design
GUI representation of the logical structure of a Database
It helps you identify the entities that exist in a system and the relationships between those entities.
ER Diagrams Symbols and Notations
Entity Relationship Diagram Symbols and Notations basically contain three basic symbols, rectangle, oval, and diamond, to represent relationships between items, entities, and attributes. ERD Diagram has some sub-elements based on main elements. An ER Diagram is a visual representation of data that describes how the data relates to each other using different ERD Symbols and Notations.
Below are the main components in the ER Diagrams:
Rectangles: This Entity Relationship Diagram symbol represents entity types
Ellipses: Symbol represents attributes
Diamonds: This symbol represents relationship types
Lines: Associates attributes to entity types and entity types with other relationship types.
Primary key: attributes are underlined
Double Ellipse: Represent multivalued attributes