In a generalization–specialization hierarchy, it must be possible to decide which entities are members of which lower level entity sets. In a condition defined design constraint, membership in the lower level entity-sets is evaluated on the BASIS of whether or not an entity satisfies an explicit condition or predicate.User-defined lower-level entity sets are not constrained by a membership condition; rather, entities are ASSIGNED to a given entity set by the database user.

Condition-defined CONSTRAINTS alone can be AUTOMATICALLY handled by the system. Whenever any tuple is inserted into the database, its membership in the various lower level entity-sets can be automatically decided by evaluating the respective membership predicates. Similarly when a tuple is updated, its membership in the various entity sets can be re-evaluated automatically.

In a generalization–specialization hierarchy, it must be possible to decide which entities are members of which lower level entity sets. In a condition defined design constraint, membership in the lower level entity-sets is evaluated on the basis of whether or not an entity satisfies an explicit condition or predicate.User-defined lower-level entity sets are not constrained by a membership condition; rather, entities are assigned to a given entity set by the database user.

Condition-defined constraints alone can be automatically handled by the system. Whenever any tuple is inserted into the database, its membership in the various lower level entity-sets can be automatically decided by evaluating the respective membership predicates. Similarly when a tuple is updated, its membership in the various entity sets can be re-evaluated automatically.