Ph.D. Thesis - Business Informatics Group

Chapter 1 Introduction
elements of the target schema are not mapped, constraints of the target schema may
be violated, e.g., if an unmapped attribute of the target schema is mandatory.
• Single correspondences: For this class, the most important property of the correspondences
is cardinality. According to the number of the participating elements in a correspondence,
it can be distinguished between one-to-one, one-to-many, many-to-one, and
many-to-many correspondences. On the instance level, one-to-one means that one element
of the source model has exactly one corresponding element in the target model,
one-to-many means that one element has to be splitted into several elements, manyto-one
means that several elements have to be combined into one element, and manyto-many
means a combination of one-to-many and many-to-one correspondences 4 .
• Multiple correspondences: This class focuses on the structure of the source schema and
the target schema. On the instance level this means, structurally related elements in
the source model should also maintain their semantic relationship in the generated
target model. Furthermore, this means, it should be possible to reproduce the original
source model from the generated target model. For ensuring semantic preserving
transformations, a set of single correspondences must be properly interpreted in combination
with the structures of source schema and target schema.
This thesis mainly deals with the two above mentioned kinds of heterogeneities, in the
area of model engineering. As a consequence, heterogeneity issues have to be considered
on higher levels of abstraction leading to the notions of meta-metamodel heterogeneity 5 at M3level
and structural metamodel heterogeneities at M2-level.
1.1.4 Model-based Tool Integration in the Context of the ModelCVS
Project
To tackle the previous mentioned problems of meta-metamodel heterogeneity and structural
metamodel heterogeneity, we developed a system called ModelCVS aiming at providing
a framework for model-based tool integration [KKK + 06b, KKR + 06]. ModelCVS enables
transparent transformation of models between different tools’ languages and exchange formats
going beyond existing low-level model transformation approaches.
As can be seen in Figure 1.2, the proposed architecture of ModelCVS is organized into
three major components. The red boxes represent tasks which are supported by tools and
4 In practice, mostly all many-to-many correspondences can be reduced to a combination of one-to-many/manyto-one
mappings. However, for specifying mappings, many-to-many mappings can at least provide a suitable
mechanism to combine correspondences, thus reducing the size and enhancing the readability of a mapping
model.
5 Although MOF is the standardized meta-metamodel of the OMG, in practice other formats are also employed as
6
meta-metamodels.