Patent ID: 7882151

Claim:
A method for processing a schema mapping M from a source schema S to a target schema T, said method performed by executing program code on a processor of a computer system, said method comprising: determining a schema mapping M′ from T to S via processing the schema mapping M, said mapping M comprising at least one constraint σ, each constraint σ consisting of a source-to-target tuple-generating dependencies (s-t tgd), said schema mapping M′ comprising at least one constraint σ′, each constraint σ′ consisting of a disjunctive tgd with constants and inequalities among the constants; and storing the schema mapping M′ in at least one computer usable storage device of the computer system and/or outputting the schema mapping M′ in at least one output device of the computer system, wherein said determining the schema mapping M′ comprises: creating an equivalent schema mapping M* from M, wherein M* comprises at least one constraint σ*, said at least one constraint σ* being a function of said at least one constraint σ; and generating the at least one constraint σ′ by inverting each constraint σ* in M* to generate the schema mapping M′ consisting of the at least one constraint σ′.