In an E-R model, what does cardinality represent?

Cardinality in an Entity-Relationship (E-R) model indicates the maximum number of times an entity can be associated with another entity within a relationship. This concept is crucial because it defines the nature of the relationship between entities, specifying how many instances of one entity can relate to instances of another.

For example, consider a relationship between a 'Customer' entity and an 'Order' entity. If the cardinality is defined as 'one to many,' it means a single customer can place multiple orders, but each order is associated with only one customer. Therefore, understanding maximum occurrences helps in designing databases that adequately reflect real-world relationships and constraints.

This focus on maximum occurrences means that other options, such as the minimum number of occurrences, average occurrences, or relationship types, do not capture the essence of what cardinality represents in an E-R model. Instead, cardinality specifically emphasizes the limits of how instances of entities can associate with each other, which is pivotal in structuring database schemas accurately.