par Van den Bussche, Jan;Van Gucht, Dirk;Vansummeren, Stijn 
Référence Proceedings of the 10th International Conference on Database Theory, ICDT 2005, Springer-Verlag, Vol. 3363, page (99-113)
Publication Publié, 2005-01
Référence Proceedings of the 10th International Conference on Database Theory, ICDT 2005, Springer-Verlag, Vol. 3363, page (99-113)
Publication Publié, 2005-01
Publication dans des actes
| Résumé : | Two natural decision problems regarding the XML query language XQuery are well-definedness and semantic type-checking. We study these problems in the setting of a relational fragment of XQuery. We show that well-definedness and semantic type-checking are undecidable, even in the positive-existential case. Nevertheless, for a ``pure'' variant of XQuery, in which no identification is made between an item and the singleton containing that item, the problems become decidable. We also consider the analogous problems in the setting of the nested relational calculus. |
