Abstract
The relational model and its extensions are often considered incompatible with object-orientation. However, on the one hand nested relations provide the complex object features demanded by object models. Particularly, powerful query languages exploit the complex data structure while keeping the advantages of the declarative, set-oriented paradigm. On the other hand, object models provide semantically rich constructs for advanced modeling, and abstractions of operations as well as data. In this paper, we show an evolutionary path from relational, essentially nested relational, to object-oriented data models and query languages. Basically, allowing nested relation schemes to be recursively defined yields the necessary flexibility w.r.t structure. The query language, i.e., nested relational algebra, carries over to this “network” model. As a first step towards the object-oriented integration of cooperative systems, different views onto the objects have to be supported. We present a powerful view definition facility that basically allows object views as well as relational views to be defined in our object algebra.
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S. Abiteboul, P. C. Fischer, and H.-J. Schek, editors. Nested Relations and Complex Objects in Databases, volume 361 of Lecture Notes in Computer Science. Springer, Heidelberg, 1989.
S. Abiteboul and P.C. Kanellakis. Object identity as a query language primitive. In Proc. ACM SIGMOD Conf. on Management of Data, pages 159–173, Portland, June 1989. ACM, New York.
A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly-typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230–260, June 1985.
F. Bancilhon. Query languages for object-oriented database systems: Analysis and a proposal. In T. Härder, editor, Proc. GI Conf. on Database Systems for Office, Engineering and Scientific Applications, pages 1–18, Zürich, March 1989. Springer IFB 204, Heidelberg.
F. Bancilhon, T. Briggs, S. Khoshafian, and P. Valduriez. FAD, a powerful and simple database language. In Proc. Int. Conf. on Very Large Databases, pages 97–105, Brighton, September 1987.
D. Beech, A foundation for evolution from relational to object databases. In J.W. Schmidt, S. Ceri, and M. Missikoff, editors, Advances in Database Technology — EDBT'88. Springer LNCS 303, March 1988.
C. Beeri. Formal models for object-oriented databases. In W. Kim, J.-M. Nicolas, and S. Nishio, editors, Proc. 1st Int'l Conf. on Deductive and Object-Oriented Databases, pages 370–395, Kyoto, December 1989. North-Holland.
R. J. Brachman and J. G. Schmolze. An overview of the KL-ONE knowledge representation system. Cognitive Science, 9:171–216, 1985.
V. Breazu-Tannen, P. Buneman, and A. Ohori. Static type-checking in object-oriented databases. IEEE Data Engineering, 12(3):5–12, September 1989. Special Issue on Database Programming Languages.
L. Cardelli and P. Wegner. On understanding types, data abstraction, and polymorphism. ACM Computing Surveys, 17(4):471–522, December 1985.
M. J. Carey, D. J. DeWitt, and S. L. Vandenberg. A data model and query language for EXODUS. In Proc. ACM SIGMOD Conf. on Management of Data, pages 413–423, Chicago, IL, May 1988. ACM, New York.
U. Dayal. Queries and views in an object-oriented data model. In R. Hull, R. Morrison, and D. Stemple, editors, 2nd Int'l Workshop on Database Programming Languages, pages 80–102, Oregon Coast, June 1989. Morgan Kaufmann, San Mateo, Ca.
U. Dayal, F. Manola, A. Buchmann, U. Chakravarthy, D. Goldhirsch, S. Heiler, J. Orenstein, and A. Rosenthal. Simplifying complex objects: The PROBE approach to modelling and querying them. In H.-J. Schek and G. Schlageter, editors, Proc. GI Conf. on Database Systems for Office, Engineering and Scientific Applications, pages 17–37, Darmstadt, April 1987. Springer IFB 136, Heidelberg.
O. Deux et al. The story of O 2. IEEE Trans. on Knowledge and Data Engineering, 2(1):91–108, March 1990. Special Issue on Prototype Systems.
K.R. Dittrich, W. Gotthard, and P.C. Lockemann. DAMOKLES — the database system for the UNIBASE software engineering environment. IEEE Database Engineering Bulletin, 10(1), March 1987.
G. Graefe and D. J. DeWitt. The EXODUS optimizer generator. In Proc. ACM SIGMOD Conf. on Management of Data, pages 160–172, San Francisco, May 1987. ACM, New York.
G. Graefe and D. Maier. Query optimization in object-oriented database systems. In K. R. Dittrich, editor, Proc. Int. Workshop on Object-Oriented Database Systems, pages 358–363, Bad Münster, September 1988. Springer LNCS 334, Heidelberg.
L.M. Haas, J.C. Freytag, G.M. Lohman, and H. Pirahesh. Extensible query processing in Starburst. In Proc. ACM SIGMOD Conf. on Management of Data, pages 377–388, Portland, OR, May 1989. ACM, New York.
S. Heiler and S.B. Zdonik. Views, data abstractions, and inheritance in the FUGUE data model. In K.R. Dittrich, editor, Advances in Object-Oriented Database Systems, Heidelberg, September 1988. Springer LNCS 334.
R. Hull and R. King. Semantic database modeling: Survey, applications, and research issues. ACM Computing Surveys, 19(3):201–260, September 1987.
W. Kim. A model of queries for object-oriented databases. In Proc. Int. Conf. on Very Large Databases, pages 423–432, Amsterdam, August 1989.
W. Lamersdorf, G. Müller, and J. W. Schmitt. Language support for office modelling. In Proc. Int. Conf. on Very Large Databases, pages 280–288, Singapore, August 1984.
P.-Å. Larson. The data model and query language of LauRel. IEEE Database Engineering Bulletin, 11(3):23–30, September 1988. Special Issue on Nested Relations.
C. Lécluse and P. Richard. Modeling complex structures in object-oriented databases. In Proc. ACM SIGACT/SIGMOD Symp. on Principles of Database Systems, pages 360–368, Philadelphia, PA, March 1989. ACM, New York.
G.M. Lohman. Grammar-like functional rules for representing query optimization alternatives. In Proc. ACM SIGMOD Conf. on Management of Data, pages 18–27, Chicago, June 1988. ACM, New York.
D. Maier. Why isn't there an object-oriented data model? Technical Report CS/E-89-002, Oregon Graduate Center, Beaverton, OR, May 1989.
B. Meyer. Object-Oriented Software Construction. International Series in Computer Science. Prentice Hall, Englewood Cliffs, 1988.
B. Mitschang. Extending the relational algebra to capture complex objects. In Proc. Int. Conf. on Very Large Databases, pages 297–305, Amsterdam, August 1989.
S.L. Osborn. Identity, equality, and query optimization. In K.R. Dittrich, editor, Advances in Object-Oriented Database Systems, pages 346–351, Heidelberg, September 1988. Springer LNCS 334.
H.-B. Paul, H.-J. Schek, M. H. Scholl, G. Weikum, and U. Deppisch. Architecture and implementation of the Darmstadt database kernel system. In Proc. ACM SIGMOD Conf. on Management of Data, San Francisco, 1987. ACM, New York.
P. Pistor and R. Traunmüller. A data base language for sets, lists, and tables. Information Systems, 11(4):323–336, December 1986.
M. A. Roth, H. F. Korth, and D. S. Batory. SQL/NF: A query language for — 1NF relational databases. Information Systems, 12(1):99–114, March 1987.
H.-J. Schek, H.-B. Paul, M.H. Scholl, and G. Weikum. The DASDBS project: Objectives, experiences and future prospects. IEEE Trans. on Knowledge and Data Engineering, 2(1):25–43, March 1990. Special Issue on Prototype Systems.
H.-J. Schek and M. H. Scholl. The relational model with relation-valued attributes. Information Systems, 11(2):137–147, June 1986.
H.-J. Schek and M. H. Scholl. The two roles of nested relations in the DASDBS project. In S. Abiteboul, P. C. Fischer, and H.-J. Schek, editors, Nested Relations and Complex Objects in Databases. Springer LNCS 361, Heidelberg, 1989.
M. H. Scholl. Theoretical foundation of algebraic optimization utilizing unnormalized relations. In ICDT '86: Int. Conf. on Database Theory, pages 380–396, Rome, Italy, September 1986. LNCS 243, Springer, Berlin, Heidelberg.
M. H. Scholl. Towards a minimal set of operations for nested relations. In M. H. Scholl and H.-J. Schek, editors, Handout Int. Workshop on Theory and Applications of Nested Relations and Complex Objects, Darmstadt, April 1987. (Position paper).
M. H. Scholl. The Nested Relational Model — Efficient Support for a Relational Database Interface. PhD thesis, Department of Computer Science, Technical University of Darmstadt, 1988. (in German).
M. H. Scholl, H.-B. Paul, and H.-J. Schek. Supporting flat relations by a nested relational kernel. In Proc. Int. Conf. on Very Large Databases, pages 137–146, Brighton, September 1987. Morgan Kaufmann, Los Altos, Ca.
M.H. Scholl, C. Laasch, and M. Tresch. Views in object-oriented databases. submitted for publication, July 1990.
M.H. Scholl and H.-J. Schek. A synthesis of complex objects and object-orientation. In Proc. IFIP TC2 Conf. on Object Oriented Databases — Analysis, Design & Construction (DS-4), Windermere, UK, July 1990. North-Holland. to appear.
G.M. Shaw and S.B. Zdonik. An object-oriented query algebra. IEEE Data Engineering, 12(3):29–36, September 1989. Special Issue on Database Programming Languages.
M.R. Stonebraker and L.A. Rowe. The design of POSTGRES. In Proc. ACM SIGMOD Conf. on Management of Data, pages 340–355, Washington, D.C., May 1986. ACM, New York.
D.D. Straube and M.T. Özsu. Query transformation rules for an object algebra. Technical Report TR 89-23, Dept. of Computing Science, University of Alberta, Edmonton, Alberta, Canada, August 1989.
D.C. Tsichritzis and O.M. Nierstrasz. Fitting round objects into square databases. In S. Gjessing and K. Nygaard, editors, Proc. European Conf. on Object-Oriented Programming, pages 283–299, Oslo, August 1988. LNCS 322, Springer Verlag, Heidelberg.
G. Wiederhold. Views, objects, and databases. IEEE Computer, December 1986.
K. Wilkinson, P. Lyngbaek, and W. Hasan. The Iris architecture and implementation. IEEE Trans. on Knowledge and Data Engineering, 2(1):63–75, March 1990. Special Issue on Prototype Systems.
N. Wirth. Type extensions. ACM Transactions on Programming Languages and Systems, 10(2):204–214, June 1988.
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Scholl, M.H., Schek, HJ. (1990). A relational object model. In: Abiteboul, S., Kanellakis, P.C. (eds) ICDT '90. ICDT 1990. Lecture Notes in Computer Science, vol 470. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-53507-1_72
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DOI: https://doi.org/10.1007/3-540-53507-1_72
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