What does term cardinality refer to in database modeling?

Cardinality in database modeling specifically refers to the minimum and maximum occurrences of an entity in relation to another entity. This concept is essential for defining how many instances of one entity can or must be associated with instances of another entity. For example, in a relationship between a customer and orders, one customer can have multiple orders, indicating a one-to-many relationship. Conversely, cardinality can also imply that a single order must be associated with exactly one customer, which establishes the rules for the relationship between these entities.

Understanding cardinality is critical for designing relational databases as it ensures that the relationships between different entities accurately reflect the desired constraints and requirements of the data model. This clarity helps prevent issues related to data integrity and ensures that the relationships are appropriately enforced within the database schema.