# Specifying the Cardinality of an Association

While creating an association with the Association Wizard or editing an association with the Association Editor, in the Association Properties page, you can specify the cardinality of an association.

Cardinality helps to define the relationship between objects by setting the minimum and maximum number of members that may participate in an association:

- 0..1 indicates that a single value is allowed, but not required

- 1 indicates that exactly one value is required

- * indicates that there are many values allowed, but none required

- 1..* indicates that at least one value is required, but many are allowed

#### To specify cardinality:

- Choose a cardinality setting for the source and destination entity objects.

Related topics
Creating a Many-to-Many Relationship