77,092 research outputs found
Facilitating evolution in relational database design : a procedure to evaluate and refine novice database designers' schemata : a thesis presented in partial fulfilment of the requirements for the degree of Master of Business Studies in Information Systems at Massey University
Relational database management systems (RDBMS) have become widely used by many industries in recent years. Latterly these systems have begun to expand their market by becoming readily available at minimal cost to most users of modern computing technology. The quality of applications developed from RDBMSs however is largely dependent upon the quality of the underlying schema. This research looks at the area of schema design and in particular schemata designed by people who have a minimal understanding of relational concepts. It uses a survey and case studies to help define some of the issues involved in the area. A procedure to modify existing schemata is described, and the schema from one of the case studies used to apply the schema re-design procedure to a real database design. The results are compared to the original schema as well as a schema designed using a conventional application of the NIAM analysis and design methodology. The research supports the hypothesis that database applications based on schemata designed by lay-persons are currently being used to support business data management requirements. The utility, reliability and longevity of these applications depend to some extent on the quality of the underlying schema and its ability to store the required data and maintain that data's integrity. The application of the schema re-design procedure presented in this thesis reveals refinements on the original schema and provides a method for lay-persons to evaluate and improve existing database designs. A number of issues and questions related to the focus of this research are raised and, although outside the scope of the research, are noted as suggestions for further work
Functorial Data Migration
In this paper we present a simple database definition language: that of
categories and functors. A database schema is a small category and an instance
is a set-valued functor on it. We show that morphisms of schemas induce three
"data migration functors", which translate instances from one schema to the
other in canonical ways. These functors parameterize projections, unions, and
joins over all tables simultaneously and can be used in place of conjunctive
and disjunctive queries. We also show how to connect a database and a
functional programming language by introducing a functorial connection between
the schema and the category of types for that language. We begin the paper with
a multitude of examples to motivate the definitions, and near the end we
provide a dictionary whereby one can translate database concepts into
category-theoretic concepts and vice-versa.Comment: 30 page
Developing Translation Rules for Converting Relational to Object Oriented Database Conceptual Schema
A multidatabase is a confederation of pre-existing distributed, heterogeneous,
and autonomous database system. Obviously, the integration process is essential
in the effort of forming a distributed, heterogeneous database system. This
process generally consists of two main phases, which are conceptual schema
translation phase followed by the integration phase. This paper presents a
translation approach to convert relational database schema to object-oriented
database schema. The translation approach consists of a set of translation rules,
which is based on inclusion dependencies, key attributes and types of attributes.
A database schema translation tool prototype, called RETOO (RElational-ToObject-
Qriented) is then developed based on the proposed translation approach.
RETOO receives a relational database schema as input data and generates an
object-oriented database schema as the output. The translation approach is not
only able to maintain the semantics of the relational database schema, but also
enhance the semantics of the translated object-oriented schema via objectoriented
data modeling concepts
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