Patent ID: RE40235

Claim:
In a computers system, a data processing system for detecting a mandatory relations violation in a relational database, said data processing system comprising: memory means containing (i) relation definition table means comprised of at least one relation type record wherein each relation type record (a) defines a relation type between two entity types and (b) includes mandatory coupling data defining mandatory coupling of said relation type, (ii) entity instance table means comprised of at least one entity instance record, and (iii) relation instance table means comprised of at least one relation instance record, wherein wash relation instance record defines a relation of a relation type defined by one of said relation type records and further wherein said relation is between a head entity instance record and a tail entity instance record, wherein said relation definition table means, said entity instance table means and said relation instance table means are part of said relational database; and means, operatively coupled to said entity instance table means and said relation instance table means, for examining a mandatory coupling of a first relation type between a first entity type and second entity type, said means for examining comprising means for determining whether said entity instance table means contains a first entity instance record of said first entity type; and means for determining whether said relation instance table means contains no relation instance record defining a relation of said first relation type between said first entity instance record and a second entity instance record of said second entity type; and means, operatively coupled to said means for examining, for indicating detection of said mandatory relations violation if said entity instance table means contains said first entity instance record of said first entity type and said relation instance table means contains no relation instance record defining a relation of said first relation type between said first entity instance record and said second entity instance record of said second entity type.