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mod06_data_structures_form.docxData Structure Form
Data Structure Form
Complete the form according to your instructions. For details, please refer to the sample completed form provided separately. The spaces expand as you write.
Table Name:
Business Rules:
List all cardinality and modality rules that apply to this data structure, rules for primary /candidate key selection, de-normalization considerations, and so on. Remember the data structure is one that comes out of the business for your project.
Data Structure: (List only one per form.)
Table Structure:
For each field identified in the data structure, complete the information in the table below.
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Tip: In the "Comments" column (far right), be sure to specify assumptions for cardinality, modality and referential integrity constraints as needed. See definition below.* |
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Column Name |
Data Type |
Allow Nulls? |
Comments: (foreign key, constraints, default) |
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* Use the following definition of referential integrity constraint:
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A constraint (rule) that specifies that the value or existence of an attribute in one relation depends on the value or existence of a primary key in another relation.
2 tables - patient/ physician - patient one physician and physician many patients. student -teacher teacher - many students
Example: Admitting Physician in Patient must exist in Physician. |
Physical Design Issues:
Estimate number of records in table, number of updates and/or queries per unit of time, issues that affect physical design such as security, joins, applications that use tables, and so on.
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Data Volume (# Records) |
Data Volatility (# of accesses per time period, % update to read access) |
Additional Considerations (Response time, Security, Performance, Applications, etc.) |
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24,000 |
How many records read each day. |
Password for security; maybe add indexes.
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© Rasmussen College 2011
