This Article 
 Bibliographic References 
 Add to: 
Extending SQL with General Transitive Closure and Extreme Value Selections
December 1990 (vol. 2 no. 4)
pp. 381-390

Many recursive query processing applications are still poorly supported, partly because implementations of general recursive capabilities are inefficient and hard to understand for users, partly because the approaches do not integrate well with existing query languages. An extension is proposed of the database language SQL for the processing of recursive structures. The new constructs are integrated in the view definition mechanism of SQL. Therefore, users with knowledge of SQL can take advantage of the increased functionally without learning a new language. The construct is based on a generalization of transitive closure and is formally defined. Because of the importance of extreme value sections, special constructs are introduced for the selection of tuples with minimal or maximal values in some attributes. Applying these selections on recursively defined views constitutes nonlinear recursion. By the introduction of special constructs for these selections, dealing with general nonlinear recursion can be avoided.

[1] R. Agrawal and H. V. Jagadish, "Direct algorithms for computing the transitive closure of database relations," inProc. 13th Int. Conf. Very Large Data Bases, Brighton, England, Sept. 1987, pp. 255-266.
[2] R. Agrawal and P. Devanbu, "Moving selections into linear least fixpoint queries," inProc. IEEE 4th Int. Conf. Data Eng., Los Angeles, CA, Feb. 1988.
[3] R. Agrawal, "Alpha: An extension of relational algebra to express a class of recursive queries,"IEEE Trans. Software Eng., vol. 14, no. 7, pp. 879-885, 1988.
[4] A. Aho and J. Ullman, "Universality of data retrieval languages," inProc. 6th ACM Symp: Principles of Programming Languages, San Antonio, TX, Jan. 1979.
[5] F. Bancilhon and R. Ramakrishnan, "An amateur's introduction to recursive query processing strategies," inProc. 1986 ACM-SIGMOD Conf. Management of Data(Washington, DC), May 1986, pp. 16-52.
[6] R. Bayer, "Database technology for expert systems," inWissensbasierte Systeme. Springer-Verlag, Informatik-Fachberichte 112, 1985, pp. 1-16.
[7] M. Brodie and J. Mylopoulos, eds.,On Knowledge Base Management Systems, Springer-Verlag, New York, N.Y., 1986.
[8] S. Ceri, G. Gottlob, and L. Tanca,Logic Programming and Databases. Berlin: Springer-Verlag, 1990.
[9] E. Codd, "Relational completeness of data base sublanguages," inData Base Systems, R. Rustin, Ed. Englewood Cliffs, NJ: Prentice-Hall, 1972, pp. 65-98.
[10] E. F. Codd, "Extending the relational database model to capture more meaning,"ACM Trans. Database Syst., vol. 4, no. 4, pp. 397-434, Dec. 1979.
[11] E. Clemons, "Design of an external schema facility to define and process recursive structures,"ACM Trans. Database Syst., vol. 6, no. 2, pp. 295-311, 1981.
[12] U. Dayal and J.M. Smith, "Probe: A knowledge-oriented database management system," in M.L. Brodie and J. Mylopoulos, Eds.,On Knowledge Base Management Systems. Berlin: Springer-Verlag, 1986.
[13] H. Gallaire, J. Minker, and J. Nicolas, "Logic and databases: A deductive approach,"ACM Comput. Surveys, vol. 16, pp. 153-185,1984.
[14] U. Guntzer and W. K. A. R. Bayer, "On evaluation of recursion in deductive database systems by efficient differential fixpoint iteration," inProc. 3rd Int. Conf. Data Engineering, 1987, pp. 120-129.
[15] J. Han, G. Qadahand, and C. Chaou, "The processing and evaluation of transitive closure queries," inAdvances in Database Technology--EDBT'88, Lecture Notes in Computer Science 303. J. W. Schmidtet al., Eds. Springer-Verlag, 1988, pp. 49-75.
[16] M. Jarke and J. Koch, "Query optimization in database systems,"ACM Comput. Surveys, vol. 16, no. 2, June 1984.
[17] L. Kerschberg, Ed.,Proc. 1st Int. Workshop Expert Database Syst., Kiawah Island, SC, 1984.
[18] L. Kerschberg,Proc. 1st Int. Conf. Expert Database Syst., Charleston, SC, 1986.
[19] H. Lu, "New strategies for computing the transitive closure of a database relation," inProc. VLDB, Brighton, 1987, pp. 267-274.
[20] D. Maier,The Theory of Relational Databases. Rockville, MD: Computer Science Press, 1983, ch. 11.
[21] R. Mittermeir and J. Eder, "XPL*SQL. Research on new AI-languages," inProc. Oracle User Group Conf., Paris, 1988.
[22] A. Rosenthal, S. Heiler, U. Dayal, and F. Manola, "Traversal recursion: a practical approach to supporting recursive applications," inProc. 1986 ACM SIGMOD Conf.(Washington, DC), 1986, pp. 166-176.
[23] H.-J. Schek, "Nested relations--A step forward or backward?,"IEEE Database Eng., vol. 11, no. 3 (Special Issue on Nested Relations), 1988.
[24] Database Language SQL, Document ANSI X3.135-1986. Also: ISO/TC97/SC21/WG3 N143.
[25] SQL*Plus User's Guide, Oracle Corp., 1987.
[26] P. Trinder and P. Wadler, "List comprehension and the relational calculus," Glasgow Univ., 1988.

Index Terms:
general transitive closure; recursive query processing applications; general recursive capabilities; existing query languages; database language SQL; recursive structures; view definition mechanism; extreme value sections; special constructs; tuples; maximal values; attributes; recursively defined views; nonlinear recursion; database management systems; information retrieval systems; query languages; standards
J. Eder, "Extending SQL with General Transitive Closure and Extreme Value Selections," IEEE Transactions on Knowledge and Data Engineering, vol. 2, no. 4, pp. 381-390, Dec. 1990, doi:10.1109/69.63250
Usage of this product signifies your acceptance of the Terms of Use.