Publications of H.D. Groger

This page shows all publications that appeared in the IASI annual research reports. Authors currently affiliated with the Institute are always listed with the full name.

You can browse through them using either the links of the following line or those associated with author names.

Show all publications of the year  ALL, with author Groger H.D., in the category IASI Research Reports (or show them all):


IASI Research Report n. 429    

Anna Formica, Groger H.D., Michele Missikoff

An efficient method for checking object-oriented database schema correctness

ABSTRACT
Inheritance is introduced in Object-Oriented Databases (ODBs) to enhance code reuse and create more compact and readable schemas. Powerful object models adopt multiple inheritance, allowing a type (or a class definition) to inherit from more than one supertype. Unfortunately, in applying this powerful modeling mechanism, inheritance conflicts may be generated, which arise when the same property, or operation, is defined in more than one supertype. Inheritance conflicts identification and resolution is the key issue of this paper. In strongly typed ODB systems the resolution of inheritance conflicts depends on the conpatibility of the typings of the conflicting definitions. In case of incompatible typings, a contradiction is identified. The goal of this paper (whose focus is on the structural part of the object model, i.e., data definition) is to provide a method aimed at supporting the designer in the construction of correct ODB schemas, for which the absence of contradictions is the first necessary condition. The second cause of schema incorrectness is the presence of structurally recursive types that, when defined within certain hierarchical patterns, cause the non-termination of the inheritance process. The paper first defines in formal terms the notion of a correct schema. Then, it describes and analyses three graph-theoretic methods aimed at verifying ODB schema correctness. While the first two methods are intuitive but inefficient, the third method allows schema correctness to be checked in polynomial time in the size of the schema. The results of this study are included in the implementation of Mosaico, an environment for ODB application design.
back
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -