Decoration

A better pattern for business logic layer.

Let me to introduce you the 3 base patterns to organize your domain logic: Transaction Script, Domain Model and Table Module.

Transaction Script
Organizes business logic by transactions. Logic for each of the CRUD operations and other business logic over data is encapsulated in one transaction script. So every transaction is a unique procedure which handles a single request from the presentation. These transactions usually do direct calls to the database like Stored procedures calls or Dynamic SQL queries.

Domain Model
An object model, which describes entities and relations between them in the domain. It’s one of the key aspects of Domain Driven Design.

Table Module
A single instance that handles the business logic for all rows in a database table or view.

For object-oriented programmers the Domain Model pattern would be the best understandable pattern, altgough many of them are still getting in touch mainly with the first Transaction Script pattern.

This article is about how Domain Model works, how to use it and how to implement it.

Domain model

Post will be written soon.

P EAA book

Development of Enterprise applications is not an easy process and there are a lot of problems you have to cope with. Martin Fowler, consultant on the design of enterprise software, has written a book clarifying architectural patterns, domain modeling, OOP programming and other patterns.

A short summary of EAA patterns can be found in his catalog.

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An extract from the book describing the contents:

The practice of enterprise application development has benefited from the emergence of many new enabling technologies. Multi-tiered object-oriented platforms, such as Java and .NET, have become commonplace. These new tools and technologies are capable of building powerful applications, but they are not easily implemented. Common failures in enterprise applications often occur because their developers do not understand the architectural lessons that experienced object developers have learned.

This book is actually two books in one. The first section is a short tutorial on developing enterprise applications, which you can read from start to finish to understand the scope of the book’s lessons. The next section, the bulk of the book, is a detailed reference to the patterns themselves. Each pattern provides usage and implementation information, as well as detailed code examples in Java or C#. The entire book is also richly illustrated with UML diagrams to further explain the concepts.

Armed with this book, you will have the knowledge necessary to make important architectural decisions about building an enterprise application and the proven patterns for use when building them.

The topics covered include:

• Dividing an enterprise application into layers
• The major approaches to organizing business logic
• An in-depth treatment of mapping between objects and relational databases
• Using Model-View-Controller to organize a Web presentation
• Handling concurrency for data that spans multiple transactions
• Designing distributed object interfaces

I recommend this book and if you cannot find it in your local library have a look on limited version of P. EAA at Google Books.

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Patterns of Enterprise Application Architecture
By Martin Fowler, David Rice, Matthew Foemmel, Edward Hieatt, Robert Mee, Randy Stafford

Publisher : Addison Wesley
Pub Date : November 05, 2002
ISBN : 0-321-12742-0
Pages : 560