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SSADM - Stage 4 |
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Data Design Stage |
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0. Introduction 1. Step 410 Carry out Relational Data Analysis 2. Step 420 Carry Out Relational Data Analysis
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Stage 4 of SSADM (Also known as the Data Design stage) invloves the design
of the data structures required by the system. Stage 4 and stage 5 are normally
performed at the same time. SSADM Stage 4 is broken into 2 seperate steps 410
and 420.
In this step tangible sources within the required system are analysed to produce an objective, bottom-up view of the data groupings and their relationships. The products of this step are the inputs to step 420.
In summary step 410 includes the following tasks:
1. Select the sources for relational data analysis.
2. Collect samples and specifications
3. Create a relational data analysis plan if one is not already included in the project plan.
4. Carry out relational data analysis on each source.
5. Optimise the result of the analysis.
6. Update the data dictionary with the results of the analysis.
In this step the results of the RDA data analysis from the previous step are merged with the requred LDS produced from the analysis phase, to form a composite logical data design. The RDA process in step 410 should reveal a number of entities, attributes and relationships which are not reflected in the current LDS. Normally the CLDD will represent an enlarged data structure to the LDS.
In summary step 420 includes the following tasks:
1. Create a data structure from the third normal form relations
2. Merge the structure of the logical data strcuture to form the composite logical data design.
3. Complete entity desricptions to reflect the structure of the CLDD.
4. Update the data dictionary to reflect the composite logical data design.