Object/Relational (O/R) Mapping

PowerDesigner supports and can automatically generate and synchronize O/R Mappings between OOM and PDM objects.

The following table lists object mappings in these two model types:

OOM Element	PDM Element
Domain	Domain
Class (if the Persistent checkbox and Generate table option are selected)	Table
Attribute Column (if the Persistent checkbox is selected)	Column
Identifier	Identifier
Association	Reference or table
Association class	Table with two associations between the end points of the association class
Generalization	Reference

You can define mappings between these two model types in any of the following ways:

Top-down – generate tables and other PDM objects from OOM classes
Bottom-up – generate classes and other OOM objects from PDM tables
Meet-in-the-middle – manually define mappings between classes and tables using the visual mapping editor

Top-Down: Mapping Classes to Tables
PowerDesigner provides default transformation rules for generating physical data models from object-oriented models. You can customize these rules with persistence settings and generation options.
Bottom-Up: Mapping Tables to Classes
PowerDesigner provides default transformation rules for generating object-oriented models from physical data models. You can enhance the generated mappings manually using the Mapping Editor.
Meet in the Middle: Manually Mapping Classes to Tables
If you have an existing OOM and PDM, you can define mappings between them manually using the Mapping Editor.

Parent topic: Object Language Definition Reference