A temporal DBMS is said to be history-oriented if:
- It supports history unique identification (e.g. via
time-invariant keys, surrogates or OIDs);
- The integrity of histories as first-class objects is
inherent in the model, in the sense that history-related integrity
constraints might be expressed and enforced, and the data
manipulation language provides a mechanism (e.g., history variables
and quantification) for direct reference to object-histories;