Chapter 8 O/R Mapping Modeling

Applying Bottom-Up Approach

Bottom-up approach is much more like top-down approach, except that transformation happens in reverse direction.

The following limitations exist when you transform an object-oriented model into a data model:

• One table just can be transformed into one class.
• Reference keys just can be transformed into bidirectional associations.
• You cannot generate inheritance links from reference keys and tables.

So you have to customize the generated OOM to meet your needs. You should define some mappings manually by following the instructions in the Meet-in-the-middle section.

There are no transformation settings for PDM elements.

To generate an OOM from a PDM:

1. Create a new PDM from scratch or by reverse engineering an existing database.
2. On the General tab define generation options: object language, name and code for the target OOM.
   
3. Select the O/R Mapping option on the Detail tab.
4. Select the PDM elements in which OOM objects will be transformed on the Selection tab.

Copyright (C) 2006. Sybase Inc. All rights reserved.