Object-Role Modeling Fundamentals: A Practical Guide to Data Modeling with ORM

by Terry Halpin

Overview

Object-Role Modeling (ORM) is a fact-based approach to data modeling that expresses the information requirements of any business domain simply in terms of objects that play roles in relationships. All facts of interest are treated as instances of attribute-free structures known as fact types, where the relationship may be unary (e.g. Person smokes), binary (e.g. Person was born on Date), ternary (e.g. Customer bought Product on Date), or longer. Fact types facilitate natural expression, are easy to populate with examples for validation purposes, and have greater semantic stability than attribute-based structures such as those used in Entity Relationship Modeling (ER) or the Unified Modeling Language (UML).

All relevant facts, constraints and derivation rules are expressed in controlled natural language sentences that are intelligible to users in the business domain being modeled. This allows ORM data models to be validated by business domain experts who are unfamiliar with ORM's graphical notation. For the data modeler, ORM's graphical notation covers a much wider range of constraints than can be expressed in industrial ER or UML class diagrams, and thus allows rich visualization of the underlying semantics.

Suitable for both novices and experienced practitioners, this book covers the fundamentals of the ORM approach. Written in easy-to-understand language, it shows how to design an ORM model, illustrating each step with simple examples. Each chapter ends with a practical lab that discusses how to use the freeware NORMA tool to enter ORM models and use it to automatically generate verbalizations of the model and map it to a relational database.

Product Details

ISBN-13:	9781634620741
Publisher:	Technics Publications
Publication date:	05/15/2015
Edition description:	UK ed.
Pages:	194
Product dimensions:	7.50(w) x 9.25(h) x 0.41(d)

Table of Contents

1 Overview of Object-Role Modeling 1
1.1 Information Modeling 1
1.2 Fact-Based Modeling 4
1.3 The Conceptual Schema Design Procedure 13
1.4 Fact-Based Modeling Tools 17
1.5 NORMA Lab 1 19
2 CSDP Steps 1-5 37
2.1 CSDP Steps 1-3 37
2.2 CSDP Step 4 45
2.3 CSDP Step 5 54
2.4 Objectification 60
2.5 NORMA Lab 2 63
3 CSDP Step 6 81
3.1 Value Constraints 81
3.2 Set-Comparison Constraints 84
3.3 Subtyping 92
3.4 NORMA Lab 3 105
4 CSDP Step 7 119
4.1 Frequency Constraints 120
4.2 Ring Constraints 123
4.3 Value-Comparison Constraints 138
4.4 Other Constraints and Final Checks 141
4.5 NORMA Lab 4 147