Building the Data Warehouse

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operational    the role of the data dictionary

development    in the development process

for data-driven development

Figure A.16 METH 16. Data warhouse development.

The data dictionary plays a central role in operational processing in the activities of ERD development and documentation, DIS development, physical database design, and coding. The data dictionary plays a heavy role in data model analysis, subject area selection, source system selection (system of record identification), and programming in the world of data warehouse development.

What about Existing Systems?

In very few cases is development done freshly with no backlog of existing systems. Existing systems certainly present no problem to the DSS component of the data-driven development methodology. Finding the system of record in existing systems to serve as a basis for warehouse data is a normal event.

A word needs to be said about existing systems in the operational environment. The first approach to existing operational systems is to try to build on them. When this is possible, much productivity is the result. But in many cases existing operational systems cannot be built on.

The second stance is to try to modify existing operational systems. In some cases, this is a possibility; in most cases, it is not.

The third stance is to do a wholesale replacement and enhancement of existing operational systems. In this case, the existing operational system serves as a basis for gathering requirements, and no more.

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