Apple WebObjects 5 Bedienungsanleitung PDF herunterladen (Seite 35)

CHAPTER 3

Enterprise Objects

The Enterprise Objects Advantage 35

 Apple Computer, Inc. January 2002

■ It’s more maintainable. With WebObjects, you don’t have to duplicate your

business logic. Thus you can easily make substantial changes to your rules

without resorting to finding and fixing every affected page in every affected

application. You can also easily track changes to your schema.

■ It improves data integrity. In WebObjects, you don’t need to rely on all

application developers to implement the business rules correctly. If one

application has an error, it is less likely to corrupt your database.

■ It scales better. In WebObjects, you can improve your application’s

performance without having to provide your users with faster systems. Instead,

you can simply move some computation-intensive processing to fast computers.

Figure 3-5 Implementing business logic in the user interface application

Another approach (Figure 3-6) is to implement your business rules in the

database—with stored procedures, rules, constraints, and triggers, for example. The

WebObjects approach betters this approach in the following ways:

■ It offers improved interactivity. If you implement your business rules in the

datasource, you need to make a round trip to the database every time the user

performs an action. Alternatively, you can batch up database changes, which

prevents the user from receiving immediate feedback. In WebObjects

applications, changes immediately appear in the user interface, but you access

the database only when saving these changes or fetching data.

Application

Relational database

Business logic

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Apple WebObjects 5 Bedienungsanleitung Seite 35