Author: Leigh van der Veen

Leigh is a former professional musician and software developer, now working full-time as a deep-dive technical writer. With a degree in musicology and post-graduate software development qualifications, she is passionate about SQL, everything database, cloud-based technologies, and infrastructure. She dives deeply into these technologies, learning everything there is to know. When not writing informative content, she spends time out in nature, walking her dogs, and making patchwork quilts.

What Is Cardinality in Data Modeling? The Theory and Practice of Database Cardinality

What is cardinality in data modeling? And how do you implement cardinality in databases? This discussion uses simple, easy-to-follow examples to describe both the theory and modeling of cardinality in ER diagrams. Cardinality is a mathematical term. It translates into the number of elements in a set. In databases, cardinality refers to the relationships between the data in two database tables. Cardinality defines how many instances of one entity are related to instances of another entity.