Database Reference
In-Depth Information
Ensure that data model conforms to
requirements
Identify and note model components
to be transformed
Transform attributes
Transform object sets
Transform instance identifiers
Transform cardinality indicators
Transform special object and
relationship types
Transform supersets and subsets
Verify that transformation
conforms to requirements
Complete data model transformation
Figure 9-2
Model transformation: major steps.
tic data model. When a project is large and the data model is expected to contain
numerous component pieces, the model transformation method is preferable. The
partial semantic data models are integrated and then transformed into a relational
data model.
Steps and Tasks
Figure 9-2 presents the major steps in the model transformation method. Study
these major steps and note how each major step enables you to proceed toward the
final transformation of the data model.
Critical Issues
Although the model transformation method for creating a relational data model
is straightforward and generally simple, you have to be concerned about a few
critical issues. In any method, there are aspects that need special attention. Let us
go over the significant issues.
Need for thoroughness.
It is important to be well-disciplined and thorough in per-
forming all the steps and tasks with utmost care. Otherwise, your final relational
data model is likely to miss significant portions of information requirements.
Long and tedious.
In the development of a large database system, the model trans-
formation method could be long and tedious. It could take a long time to complete
all portions of the information requirements. The project team needs to stay with it
and ensure that each step and each task is performed correctly.
Integration of partial models.
Again, in a large project, integration of all the partial
semantic data models put together by several data modelers could present a chal-
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