Participation constraint (ER modelling)

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A participation constraint in ER modelling may be understood as a special case of a multiplicity constraint. The participation constraint requires that an entity participates at least once in a relationship. The more general case is the multiplicity constraint which states a lower bound LOW and an upper bound UPP for the participation. The multiplicity constraint is satisfied if every entity participates at least LOW times and at most UPP times in the relationship.