A collection of properties which should be possessed by data in a href="module.php?name=Lexikon&file=search&eid=1&query=relational database">relational database. For example, in a database of family members, if we enter A as a spouse of B, we should also enter B as a spouse of A. Similarly, if we remove one end of the relationship we should also remove the other. (1998-02-18)
