## Abstract / Description of output

We study conjunctive query answering and first-order rewritability of

conjunctive queries for binary guarded existential rules. In particular, we prove

that the problem of establishing whether a given set of binary guarded existential

rules is such that all conjunctive queries admit a first-order rewriting is decidable,

and present a technique for solving this problem. These results have a

important practical impact, since they make it possible to identify those sets of

binary guarded existential rules for which it is possible to answer every conjunctive

query through query rewriting and standard evaluation of a first-order query

(actually, a union of conjunctive queries) over a relational database system.

conjunctive queries for binary guarded existential rules. In particular, we prove

that the problem of establishing whether a given set of binary guarded existential

rules is such that all conjunctive queries admit a first-order rewriting is decidable,

and present a technique for solving this problem. These results have a

important practical impact, since they make it possible to identify those sets of

binary guarded existential rules for which it is possible to answer every conjunctive

query through query rewriting and standard evaluation of a first-order query

(actually, a union of conjunctive queries) over a relational database system.

Original language | English |
---|---|

Title of host publication | Proceedings of the 30th Italian Conference on Computational Logic, Genova, Italy, July 1-3, 2015. |

Pages | 25-30 |

Number of pages | 6 |

Publication status | Published - Sept 2015 |