data:modeling:multiplicity

About

Multiplicity constrain the number of values that may be contained by a container (ie entity set)

The multiplicity specifies valid cardinalities of the collection it represents. (It denotes the possible cardinalities values of the collection)

The multiplicity is a constraint on the cardinality, which shall:

not be less than the lower bound
and not greater than the upper bound specified (unless the multiplicity is unlimited (ie *), in which case there is no constraint on the upper bound).

The properties applied to the collection of the container element.

order (ordered or not) - ie the elements can be inserted/retrieved in a specific order
unique (is unique or not) - ie does not allow duplicate

The collection type properties defines the type of collection.