Local Veri cation of Global Integrity Constraints in

We present an optimization for integrity constraint veriication in distributed databases. The optimization allows a global constraint, i.e. a constraint spanning multiple databases, to be veriied by accessing data at a single database, eliminating the cost of accessing remote data. The optimization is based on an algorithm that takes as input a global constraint and data to be inserted into a local database. The algorithm produces a local condition such that if the local data satisses this condition then, based on the previous satisfaction of the global constraint, the global constraint is still satissed. If the local data does not satisfy the condition, then a conventional global veriication procedure is required.