The concept of temporal value integrity provides a term for the characteristic distinguishing those models which represent time as just another attribute or set of attributes, from those which represent temporal values directly. The former models do not have a primitive notion of a temporal value. Instead, they have the primitive notions of time values and ordinary values, and they can represent associations between these two types of values, for example, they can represent the (non-temporal) value of a SALARY at time t. Those models with temporal value integrity have built in the primitive notion of a temporal value. In these models one can refer to a primitive temporal value like a SALARY history, as well as referring to the (non-temporal) value of a SALARY history at time t.