Generic Model Management

MMt can be divided into two parts, homogeneous and heterogeneous, dependant on whether the models we deal with are of the same or different types (metamodels). The most important issue in heterogeneous MMt is model translation, and the most difficult problem in abstract MMt is how to specify it in a generic way (so that, for example, transformations of ER-diagram into an SQL schema and the latter into an XML DTD would be particular instances of the same specification pattern). B. Concrete gMMt—Genericness across metamodels: To implement abstract MMt patterns and operations, we need to have some concrete representation of models and mappings. Moreover, this representation should be universal with respect to data models (metamodels) so that such diverse models as relational schemas, XML DTDs, or various dialects of ERand UML-diagrams would all be instances of the same universal format. The problem is evidently far from being easy. There is a reasonable fear that even if we find such a universal representation U, encoding models/mappings of some particular metamodel in U-terms can be bulky and unwieldy. Then an MMt system’s genericness (as many other sorts of genericness in software products) will be an asset for tool builders rather than for tool users. A counterproposal might be to implement model definition Figure 1. Three parts of generic MMt Table 1. What is to be done in abstract MMt (to be continued in Math-II, Table 2, p. 362) Elementary Units Repository Structure Elementary Query A Complete Query Language Data Management Value Set of relations (tables) Relational operation Relational algebra (calculus) Model Management Model, mapping ?? ?? ?? Generic MMt Heuristic MMt: Discovering correspondences and discrepancies between models, and specifying it in terms of mappings between them. Semiautomated algorithms for instantiating specification patterns. Automated part instantiation model analysis and mapping design Abstract MMt: specification patterns where internal structure of models and mappings is encapsulated (invisible) Concrete MMt: models and mappings have a concrete presentation, and operations over them are implemented via operations over these presentation Heuristic part