A constraint on the number of times that a specific attribute may be included in the same attribute group.
- Constraints on attribute in group cardinality apply only to non-redundant attributes. A redundant attribute is an attribute with a value that is subsumed by another attribute in the same group.
- Cardinality constraints are represented by square brackets containing a minimum value value represented as an integer, optionally followed by two dots and a maximum value represented as an integer or as an asterisk *.
- If the maximum is omitted then the maximum cardinality is the same as the minimum cardinality.
- If the maximum is an asterisk * the maximum cardinality is unlimited.
- Attribute in group cardinality is NOT the same as attribute group cardinality constraint.