A Model Theory for Generic Schema Management Models
ATLANTIC INTERNATIONAL UNIVERSITY
A Model Theory for Generic Schema Management Models
Kinan M Al Haffar
UM4699SIT10550D 07/08/2007
Abstract
The core of a model theory for generic schema management is developed. This theory has two distinctive features: it applies to a variety of categories of schemas, and it applies to transformations of both the schema structure and its integrity constraints. A subtle problem of schema integration is considered in its general form, not bound to any particular category of schemas. The proposed solution, as well as the overall theory, is based entirely on schema morphisms that carry both structural and semantic properties. Duality results that apply to the two levels (i.e., the schema and the data levels) are established. These results lead to the main contribution of this paper: a formal schema and data management framework for generic schema management. Implications of this theory are established that apply to integrity problems in schema integration. The theory is illustrated by a particular category of schemas with object-oriented features along with typical database integrity constraints.
1
Introduction
This paper presents the core results of a model theory for generic schema management, by which we mean schema and database transformation capabilities that are independent of a particular data model. Such transformations require major database programming tasks, such as integrating source schemas when building a data warehouse or integrating different user views into an overall database schema. In spite of nontrivial typing issues created by such transformations, database programming and other relevant paradigms have been primarily suited to dealing with structural aspects of those transformations. A major challenge is in properly addressing semantics: the integrity constraints associated with database schemas. A second major challenge is in developing such a model theory that is applicable to a variety of
A Model Theory for Generic Schema Management Models
Kinan M Al Haffar
UM4699SIT10550D 07/08/2007
Abstract
The core of a model theory for generic schema management is developed. This theory has two distinctive features: it applies to a variety of categories of schemas, and it applies to transformations of both the schema structure and its integrity constraints. A subtle problem of schema integration is considered in its general form, not bound to any particular category of schemas. The proposed solution, as well as the overall theory, is based entirely on schema morphisms that carry both structural and semantic properties. Duality results that apply to the two levels (i.e., the schema and the data levels) are established. These results lead to the main contribution of this paper: a formal schema and data management framework for generic schema management. Implications of this theory are established that apply to integrity problems in schema integration. The theory is illustrated by a particular category of schemas with object-oriented features along with typical database integrity constraints.
1
Introduction
This paper presents the core results of a model theory for generic schema management, by which we mean schema and database transformation capabilities that are independent of a particular data model. Such transformations require major database programming tasks, such as integrating source schemas when building a data warehouse or integrating different user views into an overall database schema. In spite of nontrivial typing issues created by such transformations, database programming and other relevant paradigms have been primarily suited to dealing with structural aspects of those transformations. A major challenge is in properly addressing semantics: the integrity constraints associated with database schemas. A second major challenge is in developing such a model theory that is applicable to a variety of