The Decidability of Some Restricted Implication Problems for Path Constraints

Abst ract In 10], we introduced a path constraint language and established the undecidability of its associated implication problems. In this paper, we identify several fragments of the language, and establish the decidability of the implication and nite implication problems for each of these fragments in the context of semistructured databases. In addition, we demonstrate that these fragments suuce to express important semantic information such as extent constraint, inverse relationships and local database constraints commonly found in object-oriented databases. We also show that these fragments are useful for, among other things, query optimization.

[1]  Serge Abiteboul,et al.  Inferring structure in semistructured data , 1997, SGMD.

[2]  Serge Abiteboul,et al.  Regular path queries with constraints , 1997, J. Comput. Syst. Sci..

[3]  Jeffrey D. Ullman,et al.  Representative objects: concise representations of semistructured, hierarchical data , 1997, Proceedings 13th International Conference on Data Engineering.

[4]  Jennifer Widom,et al.  The Lorel query language for semistructured data , 1997, International Journal on Digital Libraries.

[5]  Phokion G. Kolaitis,et al.  On the Decision Problem for Two-Variable First-Order Logic , 1997, Bulletin of Symbolic Logic.

[6]  Yuri Gurevich,et al.  The Classical Decision Problem , 1997, Perspectives in Mathematical Logic.

[7]  Dan Suciu,et al.  Adding Structure to Unstructured Data , 1997, ICDT.

[8]  Serge Abiteboul,et al.  Querying Semi-Structured Data , 1997, Encyclopedia of Database Systems.

[9]  Alberto O. Mendelzon,et al.  Querying the World Wide Web , 1996, Fourth International Conference on Parallel and Distributed Information Systems.

[10]  Yannis Papakonstantinou,et al.  Object Fusion in Mediator Systems , 1996, VLDB.

[11]  Dan Suciu,et al.  Query Decomposition and View Maintenance for Query Languages for Unstructured Data , 1996, VLDB.

[12]  Guido Moerkotte,et al.  Evaluating queries with generalized path expressions , 1996, SIGMOD '96.

[13]  Dan Suciu,et al.  A query language and optimization techniques for unstructured data , 1996, SIGMOD '96.

[14]  Jennifer Widom,et al.  Object exchange across heterogeneous information sources , 1995, Proceedings of the Eleventh International Conference on Data Engineering.

[15]  Jack A. Orenstein,et al.  The ObjectStore database system , 1991, CACM.

[16]  K. Jon Barwise,et al.  On Moschovakis closure ordinals , 1977, Journal of Symbolic Logic.

[17]  Dan Suciu,et al.  A Query Language and Processor for a Web-Site Management System , 1997 .

[18]  Wenfei Fan,et al.  Some Undecidable Implication Problems for Path Constraints , 1997 .

[19]  François Bancilhon,et al.  Building an Object-Oriented Database System, The Story of O2 , 1992 .

[20]  Herbert B. Enderton,et al.  A mathematical introduction to logic , 1972 .