Finite Implication of Keys and Foreign Keys for XML Data
نویسندگان
چکیده
We investigate nite implication problems associated with key and foreign key constraints for XML data. We demonstrate that there is interaction between DTDs and these constraints, and the interaction complicates the analysis of nite implication. In particular, we establish complexity results for reasoning about two classes of constraints for XML. One class, L u , deenes unary keys and foreign keys, and the other, L, consists of multi-attribute keys and foreign keys. We show that the nite implication problem for L u constraints is coNP-complete, and the nite implication problem for L constraints is undecidable. We also identify several PTIME decidable cases of the nite implication problems. In addition, we improve the results established in 16] by showing that the nite satissability problem for unary keys, unary inclusion constraints and their negations is NP-complete.
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