Structured Specification  Oracle Tips by Burleson Consulting

The Data Warehouse Development Life Cycle

The Structured Specification
Most of the system analysis methodologies provide a method for documenting logical processes, data items, and data stores. These components generally include:

* Data Flow Diagrams--A set of top-down diagrams which depict all processes within a system, the data flow among the processes, and the data stores. Figure 3.3 depicts a sample data flow diagram. The data flow diagrams (DFDs) begin at a very general level and become progressively more detailed. The lowest level of processing is called the functional primitive level, and this primitive level has been traditionally used as the starting point for systems design.

* Data Dictionary--A description of all of the logical data items, including all data flows and data stores (files). The data dictionary describes how all of the data items are stored and how they have been transformed by the processes. The data dictionary file specifications also become the foundation for the relational tables that will comprise the Oracle warehouse.

* Process Logic Specifications (mini-specs)--A description of all functional primitive processes. A process is defined as an operation that modifies a data flow. The tools used to describe processes include pseudocode, procedure flowcharts, decision trees, and decision tables.

Figure 3.3 A sample data flow diagram.