Cardinality (data modeling)

Cardinality can be used to define data models as well as analyze entities within datasets.

Computer scientist Edgar F. Codd created a systematic method to decompose and organize relational databases.

If a data model is poorly crafted, even a computer applications system with just a million records will give the end-users unacceptable response time delays.

For this reason, data modeling is a keystone in the skills needed by a modern software developer.

[4] In the object-oriented application programming paradigm, which is related to database structure design, UML class diagrams may be used for object modeling.

Two related entities shown using Crow's Foot notation. In this example, the three lines next to the song entity indicate that an artist can have many songs. The two vertical lines next to the artist entity indicate songs can only have one performer.