Database Reference
In-Depth Information
C
H A P T E R
4
Overriding the Data
Model
Even after going through IBM Cognos Report Studio Fundamentals and Advanced classes, our
students sometimes find it challenging to relate the topics learned in class to their own environ-
ment because their data just isn't organized the same way as the sample data in class.
Formatting of the reports is not as difficult as it is time-consuming; however, having the
most dazzling report does not matter one bit if it is not displaying the correct data. Getting the
correct data sometimes requires creating complex queries. This could include querying the data-
base multiple times and combining the results in ways that were not possible during the creation
of reporting models (packages). This might have been done intentionally by the developer of the
model to design a package that can provide predictable results to match most of the team's report-
ing needs.
Modelers should follow certain best practices that do not involve customizing the package
for each report. Their objective rather is to build a package that can be used to create as many
reports as possible within the scoped requirements.
Another issue that can come up is that the models are not meeting report requirements fully
due to lack of development time, modeler inexperience, or incomplete business requirements.
Report developers cannot wait for the model to change; they have to work within the existing
model and override aspects of the model instead of expecting the model to change.
The design technique of overriding the data model is not limited to a specific type of the
report and does not separate one report from the other. This technique is used in conjunction with
all other techniques discussed in this topic to create a very functional, highly formatted, and eas-
ily maintained report.
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