- Extends the fully attributed table model created through the logical database design by collecting table- and column-level data demographic information and adding it to the model.
- Provides input to the physical design of the database.
This form introduces data demographics to the ATM process. Supporting analysis requires you to determine various cumulants and then to add that data to information derived from the Column Names and Constraints and Report/Query Analysis forms.
The form supports the seventh, eighth, and ninth steps in the ATM process (see Goals of the ATM Process).
Approaches to Filling Out the Table Form
Because the determination of data demographics for columns that will be treated as multicolumn indexes is far more complex than the determination of similar data for single column index columns, the sample analysis and the way you fill out the Table form differs slightly for the single column and multicolumn situations.
The following table points to the Table form topics that apply to the two situations:
|Topic||Applies to Single Column Data?||Applies to Multicolumn Data?|
|Table Form (this topic)||Yes||Yes|
|Table Form: Basic Information||Yes||Yes|
|Table Form: Column-Level Information||Yes||Yes|
|Table Form: Miscellaneous Column-Level Information||Yes||Yes|
|Table Form: Access Information||Yes||Yes|
|Table Form: Data Demographics for Single-Column Database Objects||Yes||No|
|Maximum and Typical Column Value Frequencies||Yes||Yes|
|Table Form: Data Demographics for Multicolumn Database Objects||No||Yes|
Information Collected for the Table Forms
- Data demographics
- Column name
- Identity column
- Primary key/foreign key
- Constraint number
- Primary index/secondary indexNote the following things about this point.
- This form is filled out during the logical design phase and indexes should not be defined this soon in the process.
- A table might be a nonpartitioned NoPI object, and a table or join index might be a column-partitioned object, in which case it would not have a primary index.
- Sample data
Transcribe this information from the completed Column Names and Constraints form to the Table form.
- Value access frequency
- Join access frequency
- Join access rows
Transcribe this information from the completed Report/Query Analysis form to the Table form.
- Distinct values
- Maximum rows/value
- Typical rows/value
- Change rating
This information applies only to those columns that have been identified by the Report/Query Analysis activity as taking part in value and join accesses.
The Table form introduces data demographics to the ATM process for the first time. The sources for this information are varied and you might have to use a variety of resources to obtain the data.
Details of this activity are provided in Table Form: Data Demographics for Single-Column Database Objects.