Abstract
System evolution most often implies the integration of legacy components, such as databases, with newly developed ones, leading to mixed architectures that suffer from severe heterogeneity problems. For instance, incorporating a new program in a legacy database application can create an integrity mismatch, since the database model and the program data view can be quite different (e.g. standard file model versus OO model). In addition, neither the legacy DBMS (too weak to address integrity issues correctly) nor the new program (that relies on data server responsibility) correctly cope with data integrity management. The component that can reconciliate these mismatched subsystems is the R/W wrapper, which allows any client program to read, but also to update the legacy data, while controlling the integrity constraints that are ignored by the legacy DBMS.This article describes a generic, technology-independent, R/W wrapper architecture, a methodology for specifying them in a disciplined way, and a CASE tool for generating most of the corresponding code.The key concept is that of implicit construct, which is a structure or a constraint that has not been declared in the database, but which is controlled by the legacy application code. The implicit constructs are elicited through reverse engineering techniques, and then translated into validation code in the wrapper. For instance, a wrapper can be generated for a collection of COBOL files in order to allow external programs to access them through a relational, object-oriented or XML interface, while offering referential integrity control. The methodology is based on a transformational approach that provides a formal way to build the wrapper schema and to specify inter-schema mappings.
- Aiken, P., 1996. Data Reverse Engineering. McGraw-Hill.]]Google Scholar
- Balzer, R. 1981. Transformational implementation : An example. IEEE TSE 7, 1, 3--14.]]Google Scholar
- Bergamaschi, S., Castano, S., Beneventano, D., and Vinci, M. 2001. Semantic Integration of Heterogeneous Information Sources. Data Knowl. Eng. 36, Elsevier, 215--249.]] Google Scholar
- Blaha, M. R. and Premerlani, W. J. 1995. Observed Idiosyncrasies of Relational Database designs. In Proceedings of the 2nd IEEE Working Conference on Reverse Engineering, Toronto, July, IEEE Computer Society Press.]] Google Scholar
- Bouguettaya, A., Benetallah, B., and Elmagarmid, A. 1998. Interconnecting Heterogeneous Information Systems. Kluwer Academic Publishers.]] Google Scholar
- Brodie, M. and Stonebraker, M. 1995. Migrating Legacy Systems, Morgan Kaufmann.]]Google Scholar
- Carey, M. J., Florescu, D., Zachary, G. I., and Ying, L. 2000. XPERANTO: Publishing Object-Relational Data as XML. In Proceedings of WebDB (Informal Proceedings), 105--110.]]Google Scholar
- Edwards, H. and Munro, M. 1995. Deriving a Logical Model for a System Using Recast Method. In Proceedings of the 2nd WCRE Conference, Toronto, IEEE Computer Society Press.]] Google Scholar
- Englebert, V. and Hainaut, J.-L. 1999. DB-MAIN: A Next Generation Meta-CASE. Inform. Syst. J. 24, 2. Pergamon, 99--112.]] Google Scholar
- Fernandez, M., Tan, W., and Suciu, D. 2000. Silkroute: Trading between Relations and XML. Comput. Netw. 33, Elsevier, 723--745.]] Google Scholar
- Fikas, S., F. 1985. Automating the Transformational Development of Software, IEEE TSE 11, 1268--1277.]] Google Scholar
- Garcia-molina, H., Papakonstantinou, Y., Quass, D., Rajaraman, A., Sagiv, Y., Ullman, J. D., Vassalos, V., and Widom, J. 1997. The TSIMMIS Approach to Mediation: Data Models and Languages. J. Intell. Inform. Syst. 8, 2, 117--132.]] Google Scholar
- Gray, P. 1993. Query Evaluation Techniques for Large Databases. ACM Comput. Surv. 25, 2, 73--170.]] Google Scholar
- Hainaut, J.-L., Chandelon M., Tonneau, C., and Joris, M. 1993. Transformational techniques for database reverse engineering. In Proceedings of the 12th International Conference on ER Approach, ER Institute, 364--375.]] Google Scholar
- Hainaut, J.-L., Henrard, J., Roland, D., and Englebert, V. 1996. Database Design Recovery, in Proceedings of the 8th Conference on Advanced Information Systems Engineering (CAiSE), Springer-Verlag, 272--300.]] Google Scholar
- Hainaut, J.-L. 2002. Introduction to Database Reverse Engineering. LIBD Lecture Notes, University of Namur. http://www.info.fundp.ac.be/~dbm/publication/2002/DBRE-2002.pdf; October 2005.]]Google Scholar
- Hainaut, J.-L. 2005. Transformation-Based Database Engineering. In Transformation of Knowledge, Information and Data: Theory and Applications. P. van Bommel, Ed. IDEA Group, 1--28.]] Google Scholar
- Henrard, J. and Hainaut, J.-L. 2001. Data Dependency Elicitation in Database Reverse Engineering. In Proceedings of the 5th European Conference on Software Maintenance and Reengineering (CSMR), IEEE Computer Society Press, 11--19.]] Google Scholar
- Henrard, J., Hick, J.-M. Thiran, Ph., and Hainaut, J.-L. 2002. Strategies for Data Reengineering. In Proceedings of the WCRE Conference, Richmond, IEEE Computer Society Press, 211--220.]] Google Scholar
- Hick, J.-M., Englebert, V., Henrard, J., Roland, D., and Hainaut, J.-L. 2004. The DB-MAIN Database Engineering CASE Tool (version 7.1)---Functions Overview, DB-MAIN Technical Manual, Institut d'Informatique, University of Namur. http://www.rever-sa.com/DISTRIBUTION/VERSION.7/DB-MAIN-Reference-Manual.pdf; October 2005]]Google Scholar
- Lawrence, R., Barker, K., and Adil, A. 1998. Simulating MDBS Transaction Management Protocols. In Proceedings of the CAINE Conference.]]Google Scholar
- Lee, H. and Yoo, C. 2000. A Form Driven Object-Oriented Reverse Engineering Methodology, Inform. Syst. 25, 3. Elsevier, 235--259.]] Google Scholar
- Lim, E. P. and Lee, H. K. 1999. Export Database Derivation in Object-Oriented Wrappers. Inform. Softw. Tech. 41, Elsevier, 183--196.]]Google Scholar
- Lopes, S., Petit, J.-M., and Toumani, F. 2002. Discovering Interesting Inclusion Dependencies: application to logical database tuning, Inform. Syst. 27, Elsevier, 1--19.]] Google Scholar
- Masunaga, Y. 1984. A Relational Database View Update Translation Mechanism. In Proceedings of the 10th International Conference on Very Large Data Bases, Morgan Kaufmann, 309--320.]] Google Scholar
- McBrien, P. and Poulovassilis, A. 1998. A General Formal Framework for Schema Transformation, Data Knowl. Eng. 28, 1, Elsevier, 47--71.]] Google Scholar
- Novelli, N. and Cicchetti, R. 2001. Functional and Embedded Dependency Inference: a Data Mining Point of View, Inform. Syst. 26, 477--506.]] Google Scholar
- Petit, J.-M., Kouloumdjan, J., Bouliaut, J.-F., and Toumani, F. 1994. Using Queries for Improving Database Reverse Engineering. In Proceedings of the 13th International Conference on ER Approach, Manchester, Springer-Verlag.]] Google Scholar
- Proper, H. A. and Halpin, T. A. 1998. Database Schema Transformation & Optimization. In Proceedings of the 14th International Conference on Conceptual Modeling, LNCS, 1021, Springer, 191--203.]] Google Scholar
- Rauh, O. and Stickel, E. 1995. Standard Transformations for the Normalization of ER Schemata. In Proceedings of the CAiSE95 Conference, Jyväskylä, Finland, LNCS, Springer-Verlag, 313--326.]] Google Scholar
- Ritsch, H. and Sneed, H. 1993. Reverse Engineering Programs via Dynamic Analysis. In Proceedings of the 1st IEEE Working Conf. on Reverse Engineering. Baltimore, IEEE Computer Society Press, 192--201.]]Google Scholar
- Rosenthal, A. and Reiner, D. 1988. Theoretical Sound Transformations for Practical Database Design. In Proceedings of Entity-Relationship Approach. LNCS, Springer-Verlag, 115--131.]] Google Scholar
- Ross, W. 1993. Hewlett-Packard's Migration to Client/Server Architecture. In Distributed Computing: Implementation and Management Strategies, Prentice Hall, ed. Khanna, M.]] Google Scholar
- Roth, M. and Schwarz, P. 1997. Don't Scrap It, Wrap it! A Wrapper Architecture for Legacy Data Sources. In Proceedings of the VLDB Conference. Morgan Kaufmann, 266--275.]] Google Scholar
- Shanmugasundaram, J., Kiernan, J., Shekita, E. J., Fan, C., and Funderburk, J. 2001. Querying XML Views of Relational Data. In Proceedings of the 27th VLDB Conference. Morgan Kaufmann, 261--270.]] Google Scholar
- Souder, T. and Mancoridis, S. 1999. A Tool for Securely Integrating Legacy Systems into Distributed Environment. In Proceedings of the 6th WCRE Conference. IEEE CS Press, 47--55.]] Google Scholar
- Thiran, Ph. and Hainaut, J.-L. 2001. Wrapper Development for Legacy Data Reuse. In Proceedings of the WCRE Conference. Stuttgart, Germany, October, IEEE CS Press, 198--207.]] Google Scholar
- Thiran, Ph., Houben, G.-J., Hainaut J.-L. and Benslimane, D. 2004. Updating Legacy Databases through Wrappers: Data Consistency Management. In Proceedings of WCRE'04, IEEE CS Press, 58--67.]] Google Scholar
- Thiran, Ph., Hainaut, J.-L., Houben, G.-J. 2005a. Database Wrappers Development. Towards Automatic Generation. In Proceedings of the CSMR Conference. Manchester, March, IEEE Computer Society Press, 207--216.]] Google Scholar
- Thiran, Ph., Estievenart, F., Hainaut, J.-L. and Houben, G. J. 2005b. A Generic Framework for Extracting XML Data from Legacy Databases. Journal of Web Engineering, 4, 3, Rinton Press, 205--223.]] Google Scholar
- Weiser, M. 1984. Program Slicing, IEEE TSE 10, 352--357.]]Google Scholar
- Wu, B., Lawless, D., Bisbal, J., Grimson, J., Wad, V., O'sullivan, D., and Richardson, R. 1997. Legacy System Migration: A Legacy Data Migration Engine, In Proceedings of the 17th International Database Conference (DATASEM '97), Ed. Czechoslovak Computer Experts, 129--138.]]Google Scholar
- Yang, H. and Bennett, K. H. 1995. Acquisition of ERA Models from Data Intensive Code. In Proceedings of the International Conference on Software Maintenance, ICSM '95, Opio (Nice), France, October 17--20. IEEE Computer Society, 116--123.]] Google Scholar
Index Terms
- Wrapper-based evolution of legacy information systems
Recommendations
A generic framework for extracting XML data from legacy databases
This paper describes a generic framework of which semantics-based XML data can be derived from legacy databases. It consists in first recovering the conceptual schema of the database through reverse engineering techniques, and then in converting this ...
Constraint Preserving Transformation from Relational Schema to XML Schema
XML has become the standard for publishing and exchanging data on the Web. However, most business data is managed and will remain to be managed by relational database management systems. As such, there is an increasing need to efficiently and accurately ...
Database application evolution: a transformational approach
Special issue: ER 2003While recent data management technologies, such as object oriented techniques, address the problem of database schema evolution, standard information systems currently in use raise challenging evolution problems. This paper examines database evolution ...
Comments