Tractable query languages for complex object databases

The expressiveness and complexity of several calculus-based query languages for complex objects are considered. Unlike previous investigations, we are concerned with the complexity of queries on databases of complex objects, rather than flat databases. This raises new issues specific to complex objects. For instance, it is shown that the way the database makes use of its higher-order types has direct impact on query complexity. The use of fixpoint operators is shown to yield languages well-behaved with respect to complexity and expressiveness. In particular, an extension of the fixpoint queries to complex objects is shown to express precisely the PTIME queries, under the assumption that the database makes "full" use of all its types. Similar results involve range-restricted queries.

[1]  Gabriel M. Kuper,et al.  On the Complexity of Queries in the Logical Data Model , 1993, Theor. Comput. Sci..

[2]  Serge Abiteboul,et al.  A rule-based language with functions and sets , 1991, TODS.

[3]  Playing Games with Objects , 1990, ICDT.

[4]  Serge Abiteboul,et al.  Non-deterministic languages to express deterministic transformations , 1990, PODS '90.

[5]  S. Abiteboul,et al.  Fixpoint extensions of first-order logic and datalog-like languages , 1989, [1989] Proceedings. Fourth Annual Symposium on Logic in Computer Science.

[6]  Serge Abiteboul,et al.  Object identity as a query language primitive , 1989, SIGMOD '89.

[7]  Jianwen Su,et al.  Untyped sets, invention, and computable queries , 1989, PODS '89.

[8]  Jianwen Su,et al.  On the expressive power of database queries with intermediate types , 1988, PODS '88.

[9]  Dirk Van Gucht,et al.  Possibilities and limitations of using flat operators in nested algebra expressions , 1988, PODS '88.

[10]  Gabriel M. Kuper.  On the expressive power of logic programming languages with sets , 1988, PODS '88.

[11]  Catriel Beeri,et al.  Sets and negation in a logic data base language (LDL1) , 1987, PODS.

[12]  Gabriel M. Kuper,et al.  Logic programming with sets , 1987, J. Comput. Syst. Sci..

[13]  Anne Verroust-Blondet,et al.  VERSO: A Database Machine Based On Nested Relations , 1987, NF².

[14]  Catriel Beeri,et al.  On the power of languages for manipulation of complex objects , 1987, VLDB 1987.

[15]  Serge Abiteboul,et al.  Non First Normal Form Relations: An Algebra Allowing Data Restructuring , 1986, J. Comput. Syst. Sci..

[16]  Hans-Jörg Schek,et al.  The relational model with relation-valued attributes , 1986, Inf. Syst..

[17]  Neil Immerman,et al.  Relational Queries Computable in Polynomial Time , 1986, Inf. Control..

[18]  Saharon Shelah,et al.  Fixed-point extensions of first-order logic , 1985, 26th Annual Symposium on Foundations of Computer Science (sfcs 1985).

[19]  Serge Abiteboul,et al.  IFO: a formal semantic database model , 1987, TODS.

[20]  Gabriel M. Kuper,et al.  A new approach to database logic , 1984, PODS.

[21]  Moshe Y. Vardi.  The complexity of relational query languages (Extended Abstract) , 1982, STOC '82.

[22]  Barry E. Jacobs,et al.  On Database Logic , 1982, JACM.

[23]  David Harel,et al.  Computable Queries for Relational Data Bases , 1980, J. Comput. Syst. Sci..