Designing XML Based Applications
fines transformations on the internal schema to support the external schemas.
3. An in to out approach, or legacy adapter This approach is actually about
how to map an application data model to schemas. The developer designs the
exposed schema from an existing data model.
Figure 4.4, Figure 4.5, and Figure 4.6 show the sequencing of the activities
involved at design time and the artifacts (schemas and classes) used or produced
by these activities. The figures also show the relationships between these artifacts
and the runtime entities (documents and objects), as well as the interaction at
runtime between these entities.
The first approach (Figure 4.4), which introduces a strong dependency
between the application's data model and logic and the external schemas, is suit
able only for applications dedicated to supporting a specific interaction model. A
strong dependency such as this implies that evolving or revising the external
schemas impacts the application's data model and its logic.
(1) Design Data
Out to In Approach for Mapping Schemas to the Data Model Classes