Building the Data Warehouse

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M3—Sizing, Phasing


PRECEDING ACTIVITY: Using existing code/data.


FOLLOWING ACTIVITY: Requirements formalization; capacity analysis.


TIME ESTIMATE: This step goes rapidly, usually in a day or two, even for the largest of designs.


NORMALLY EXECUTED ONCE OR MULTIPLE TIMES: Once, then revisited for each continuing phase of development.


DELIVERABLE: Identification of phases of development.


After the general requirements are gathered, the next step is to size them and divide development up into phases. If the system to be developed is large, it makes sense to break it into development phases. In doing so, development is parceled out in small, manageable units. Of course, the different development phases must be organized into a meaningful sequence, so that the second phase builds on the first, the third phase builds on the first and second, and so on.


The output from this step is the breakup of general requirements into doable, manageable phases, if the requirements are large enough to require a breakup at all.


PARAMETERS OF SUCCESS: To continue the development process in increments that are both economic and doable (and within the political context of the organization as well).


M4—Requirements Formalization


PRECEDING ACTIVITY: Sizing, phasing.


FOLLOWING ACTIVITY: ERD specification; functional decomposition.


TIME ESTIMATE: Indeterminate, depending on size of system, how well the scope of the system has been defined, and how ambiguous the design is up to this point.


NORMALLY EXECUTED ONCE OR MULTIPLE TIMES: Once per phase of development.


DELIVERABLE: Formal requirements specification.


Once the requirements have been gathered, sized, and phased (if necessary), the next step is to formalize them. In this step, the developer ensures the following:

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