Understanding ERD. Definition of (entities, attributes, cardinalities and relationships)

Understanding ERD

(ERD) is the abbreviation if this term entity relationship diagram, also known as an entity relationship model, is a graphical depiction of the relationships that exist between people, things, locations, concepts, or events in an information technology (IT) system. An ERD employs data modelling approaches to assist in the definition of business processes and as the foundation for a relational database (Techtarget, 2022).

Here are the difrences between the (ERD):

v  Entity:

These forms are independent of other entities and are frequently referred to as parent entities since they frequently rely on weak entities. They will also have a primary key that will differentiate each instance of the object (Lucidchart, 2022).

v  Relationship:

Relationships are relationships formed by or between things (Lucidchart, 2022).

v  Attribute:


Attributes are qualities of an entity, a many-to-many or one-to-one connection (Lucidchart, 2022).


References:

Lucidchart, 2022. Entity-Relationship Diagram Symbols and Notation. [online] Lucidchart. Available at: <https://www.lucidchart.com/pages/ER-diagram-symbols-and-meaning#:~:text=Attributes%20are%20characteristics%20of%20an,calculated%20from%20related%20attribute%20values.> [Accessed 14 August 2022].

Techtarget, 2022. What is Entity Relationship Diagram (ERD)? - Definition from WhatIs.com. [online] SearchDataManagement. Available at: <https://www.techtarget.com/searchdatamanagement/definition/entity-relationship-diagram-ERD> [Accessed 14 August 2022].

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