Mapping strategies

Application Developer supports three mapping strategies for entity beans and relationships:

  • Top-down— From entity beans to new tables

  • Bottom-up— From existing tables to new entity beans

  • Meet-in-the-middle— Map entity beans to existing tables

Figure 12-1 summarizes the three approaches.

Figure 12-1. Mapping strategies for CMPs

In the sections that follow, we look at the three strategies in detail.

Top-down

The top-down approach is the easiest to handle, because no legacy database is imposed on you (Figure 12-2). You have full freedom to design the entity beans.

Figure 12-2. EJB mapping: top-down approach

The top-down approach ...

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