What is cardinality?

Cardinality specifies how many values can be assigned to an attribute or role.

the number of values for a given attribute or role can be controlled by a minimum expected number (minimum cardinality), or a maximum number not to be exceeded (maximum cardinality). In ITM the cardinalities are indicated with a notation between square brackets.

Here are the cardinalities that you will generally encounter:

• [0:*]: optional value. Several values can be filled in.
• [0:1]: optional value. Only one value can be filled in.
• [1:1]: mandatory value. Only one value must be filled in.
• [1:*]: mandatory value. One or more values must be filled in.

When editing a topic, error messages will warn you if the cardinalities are not respected.