Eclipse XA Series Manual do Utilizador descarregar pdf (Página 61)

Application Data Model

While analyzing a legacy system it is important to understand the application’s design. An analyst

looks for the implicit Data Model information of the legacy system, which is the foundation for the

application’s design.

Extracting the implicit Data Model from a legacy system is a tedious task and more importantly it

requires legacy skill set, which is diminishing in present scenario. To accomplish this task manually

would take months and even after that it would not guarantee its correctness.

In context to the X-Analysis, the term Data Model not only refers to physical model of the database

design but also refers to the foreign key or relational model. The Relational Data Model is the most

valuable asset for an organization; it is an extremely powerful piece of information. It can be reused in

a number of scenarios.

The X-Analysis automatically derives an explicit physical & logical data model by analyzing both the

actual data contents and all programs that use this data to verify the existence of any

cross-file relationships. These potential relationships are then verified by performing an integrity check

to ensure that all data from the dependant file does indeed, validly refers data records from the

owning file.

A complete data model accurately describing all possible relationships between each file is essential

for productive maintenance and development work. Such a model also provides the foundation upon

which critical data administration tasks such as referential integrity testing, and test data extraction

can be automated.

The graphical representation of the automatic generated Data Model information in the X-Analysis is

termed as ‘Data Model Diagram’. The Data Model Diagram displays the file relationships for an

Application / Application Area.

To build the Data Model, it is necessary to execute the Modeling Command on IBM i. For details

about the modeling command, refer to the ‘X-Analysis User Manual’.

Generating Data Model Diagram

Double click on the ‘Data Model Diagram’ node under the cross-reference library ‘XAN4CDXA’.

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Eclipse XA Series Manual do Utilizador Página 61