Abstract
Motivated by the need to export relational databases as XML data in the context of the Web, we investigate the typechecking problem for transformations of relational data into tree data (XML). The problem consists of statically verifying that the output of every transformation belongs to a given output tree language (specified for XML by a DTD), for input databases satisfying given integrity constraints. The typechecking problem is parameterized by the class of formulas defining the transformation, the class of output tree languages, and the class of integrity constraints. While undecidable in its most general formulation, the typechecking problem has many special cases of practical interest that turn out to be decidable. The main contribution of this article is to trace a fairly tight boundary of decidability for typechecking in this framework. In the decidable cases we examine the complexity, and show lower and upper bounds. We also exhibit a practically appealing restriction for which typechecking is in PTIME.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
