Download PDFOpen PDF in browserIncorporating Hypothetical Views and Extended Recursion into SQL Database Systems14 pages•Published: July 28, 2014AbstractCurrent database systems supporting recursive SQL imposerestrictions on queries such as linearity, and do not implement mutual recursion. In a previous work we presented the language and prototype R-SQL to overcome those drawbacks. Now we introduce a formalization and an implementation of the database system HR-SQL that, in addition to extended recursion, incorporates hypothetical reasoning in a novel way which cannot be found in any other SQL system, allowing both positive and negative assumptions. The formalization extends the fixpoint semantics of R-SQL. The implementation improves the eciency of the previous prototype and is integrated in a commercial DBMS. Keyphrases: databases, fixpoint semantics, hypothetical queries, recursion In: Ken Mcmillan, Aart Middeldorp, Geoff Sutcliffe and Andrei Voronkov (editors). LPAR-19. 19th International Conference on Logic for Programming, Artificial Intelligence and Reasoning, vol 26, pages 9-22.
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