Using Existing Relational Schema
This section shows one way to use an existing relational schema to create an object schema. Key points are:
- Ways to use type codes and relational views to get ideas about the object class hierarchy.
- A step-by-step example of converting a relational schema to an object schema and checking to ensure no information is lost in the process.
- Adding method code that was not in the relational schema to the object schema.
To view the steps for this technique in order, just follow the Next link that appears below and on each of the pages in this section. You can also skip around by using the menu choices that appear at the bottom of each page.
You may notice that the notation is somewhat different from current UML diagramming. These diagrams were created prior to the latest UML diagramming conventions. Nevertheless, the meaning in the diagrams should be obvious.
For more information on this technique, see The Object Database Handbook, which is the source of these diagrams.
Next: Type codes. Also see the related content below.
More detail for the current topic: Using Existing Relational Schema
- Type Codes
- Using Type Codes to Construct Classes
- Multi-Type Views
- Checking the Class Hierarchy
- Adding Method Code
- Using the Data
More on the general topic: Object-Relational Mapping Articles
- Object-Relational Mapping (OR Mapping) Definition
- When Object-Relational Mapping Should Be Used
- Basic Concepts for Using Object-Relational Mapping
- Mapping Layer
- Writing Your Own Mapping Layer
- Article Suggestions