Storage and retrieval of database constraints

摘要

First order static database constraints are expressed in terms of updates that may violate them, and the updates that will block those violations. Such simple necessary conditions for violations, and sufficient conditions for validations are useful in storing database constraints on secondary storage devices, maintaining them using relational database management systems, and retrieving them using database query languages. Considerable efficiency in constraint management is achieved by retrieving only the relevant constraints for each database stransaction. A large proportion of constraints are eliminated from consideration without retrieval from the storage device, and without any significant processing. Storage structure provides indexing with respect to relations, constants, quantifiers, and arbitrary join conditions.