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Business Objects

The most important part of applications that use the Enterprise Object technology are the application’s enterprise object instances—your application’s business objects. Designing these objects is one of the primary tasks in developing an Enterprise Objects application. This chapter explains the structure of enterprise objects, how they interact with other parts of the technology, and how you can leverage the power of the technology in your custom enterprise object classes.

Designing enterprise objects entails three major steps:

• Designing a database schema

• Modeling enterprise objects

• Implementing enterprise object classes

This chapter briefly discusses the first two steps but leaves the details to EOModeler User Guide. This chapter focuses on the third step, implementing enterprise object classes. The chapter is divided into these sections:

• “Reference Entity” introduces a simple entity object that is referred to throughout the chapter.

• “Designing a Schema” discusses how design decisions in database schemas and in their corresponding enterprise object models affect one another.

• “Defining the Model” discusses the earliest design decisions you make about enterprise objects classes, which are reflected in your application’s data model.

• “Which Enterprise Object Class?” discusses the various concrete implementations of the EOEnterpriseObject interface.

• “Choosing Class Properties” discusses how to choose class properties.

• “Relationships With Other Enterprise Objects” discusses relationships between enterprise objects.

• “Referential Integrity” discusses the referential integrity rules you can build into enterprise objects.

• “Implementing an Enterprise Object” discusses how to implement an enterprise object class.

• “Accessing an Enterprise Object’s Data” discusses how to use key-value coding to access an enterprise object’s data.

• “Common Programming Errors” discusses some common mistakes in implementing enterprise object classes.

• “Synchronizing Model Changes to Class Files” discusses how to merge model changes with existing enterprise object class files.

• “Instantiating Enterprise Objects” discusses common ways to instantiate enterprise objects programmatically.

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