Model-Independent Schema and Data Translation

Abstract

Abstract. We describe MIDST, an implementation of the model management operator ModelGen, which translates schemas from one model to another, for example from OO to SQL or from SQL to XSD. It extends past approaches by translating database instances, not just their schemas. The operator can be used to generate database wrappers (e.g. OO or XML to relational), default user interfaces (e.g. relational to forms), or default database schemas from other representations. The approach translates both schemas and data: given a source instance I of a schema S expressed in a source model, and a target model TM, it generates a schema S expressed in TM that is "equivalent" to S and an instance I of S "equivalent" to I. A wide family of models is handled by using a metamodel in which models can be succinctly and precisely described. The approach expresses the translation as Datalog rules and exposes the source and target of the translation in a generic relational dictionary. This makes the translation transparent, easy to customize and model-independent.

Model Driven Specification of Ontology Translations

“…The work of Atzeni et al [19] is based on a metamodel approach with models described in terms of the constructs they involve, taken from a given set of predefined ones. However, the work is in the scope of databases and does not support reasoning at the semantic layer.…”

MISM: A Platform for Model-Independent Solutions to Model Management Problems

“…It is based on our experience in the MIDST platform [3][4][5], where a modelindependent approach for schema and data translation was introduced (with a generic implementation of the modelgen operator). MIDST adopts a metalevel approach in which the artifacts of interest are handled in a repository that represents data models, schemas, and databases in an integrated way, both model-independent and model-aware.…”

“…This has usually been done by adopting some "universal data model," a model that is more general than the various models of interest in a heterogeneous framework. In the literature, such a data model is called universal metamodel [11] or supermodel [3,6]. If the operations of interest also include translations from a data model to another (the modelgen operator), it is important that the individual data models are represented, in such a way that it becomes possible to describe the fact that a schema belongs to a data model.…”

“…We will call this property model-awareness. The various proposals for modelgen [3,6,25,26] do include the model independence feature, to a larger or lesser extent. For the other operators, the major efforts in the model management area (as summarized by Bernstein and Melnik [11]) do not handle the explicit representation of data models nor generic definitions of the operators.…”

Schema Exchange: A Template-Based Approach to Data and Metadata Translation

“…The ModelGen operator realizes a schema translation from a source data model M s to a target data model M t of schemas conforming to M s , for instance, a translation of a schema from the ER to an XML-based data model. Several approaches to this problem have been proposed in the last years [1,7,15,17]. In this paper, we provide a novel contribution to this problem by studying a framework for schema translation with a clear and precise semantics, that can be at the basis of an innovative tool supporting an important activity of model management.…”