Monadic Datalog and Regular Tree Pattern Queries

Containment of monadic datalog programs over trees is decidable. The situation is more complex when tree nodes carry labels from an infinite alphabet that can be tested for equality. Then, it matters whether descendant relation is allowed or not: descendant relation can be eliminated easily from monadic programs only when label equalities are not used. With descendant, even containment of linear monadic programs in unions of conjunctive queries is undecidable and positive results are known only for bounded-depth trees.

[1]  Letizia Tanca,et al.  Logic Programming and Databases , 1990, Surveys in Computer Science.

[2]  Haim Gaifman,et al.  Decidable optimization problems for database logic programs , 1988, STOC '88.

[3]  Floris Geerts,et al.  XPath satisfiability in the presence of DTDs , 2008, JACM.

[4]  Serge Abiteboul,et al.  Foundations of Databases , 1994 .

[5]  Diego Calvanese,et al.  Decidable containment of recursive queries , 2003, Theor. Comput. Sci..

[6]  Surajit Chaudhuri,et al.  On the equivalence of recursive and nonrecursive datalog programs , 1992, J. Comput. Syst. Sci..

[7]  Dan Suciu,et al.  Containment and equivalence for a fragment of XPath , 2004, JACM.

[8]  Oded Shmueli,et al.  Equivalence of DATALOG Queries is Undecidable , 1993, J. Log. Program..

[9]  Diego Figueira,et al.  Satisfiability of downward XPath with data equality tests , 2009, PODS.

[10]  Michael Benedikt,et al.  Monadic Datalog Containment , 2012, ICALP.

[11]  Serge Abiteboul,et al.  Recursive queries on trees and data trees , 2013, ICDT '13.

[12]  Serge Abiteboul,et al.  On the equivalence of distributed systems with queries and communication , 2011, ICDT '11.

[13]  Georg Gottlob,et al.  Conjunctive queries over trees , 2006, J. ACM.

[14]  Piero A. Bonatti,et al.  On the decidability of containment of recursive datalog queries - preliminary report , 2004, PODS '04.

[15]  Haim Gaifman,et al.  Decidable Optimization Problems for Database Logic Programs (Preliminary Report) , 1988, STOC 1988.

[16]  Thomas Schwentick,et al.  On the complexity of XPath containment in the presence of disjunction, DTDs, and variables , 2006, Log. Methods Comput. Sci..

[17]  Harry G. Mairson,et al.  Undecidable optimization problems for database logic programs , 1993, JACM.