Source : Free On-Line Dictionary of Computing

integrity constraint
     
         A {constraint} (rule) that must remain true for a
        {database} to preserve {integrity}.  Integrity constraints are
        specified at database creation time and enforced by the
        {database management system}.
     
        Examples from a genealogical database would be that every
        individual must be their parent's child or that they can have
        no more than two natural parents.
     
        (1995-11-11)