Subject Areas

Overview of Subject Areas

1)   Oracle BI Applications provides preconfigured subject areas.

2)   You can change these preconfigured subject areas or create new subject areas to correspond to your particular business processes.

Note: To change a preconfigured subject area or to create a new

subject area, you must first make a copy of an existing source system

container or create a new container. For instructions, see "Creating or

Copying a Source System Container".

Designing a Subject Area

In designing a subject area, you should consider the following questions:

■ Tables.

Which tables need to be populated for the data warehouse? From which tables does your organization source data?

What tables will create the star schemas.

■ Subject areas. Do the subject areas cover all the relevant tables?

■ Tasks. Are the tasks that load this table defined?

■ Indexes. Do the target tables have the correct indexes defined?

Previewing and Pruning Subject Areas

1)   You can preview a subject area to determine whether it contains the appropriate tables and tasks to suit your business needs.

2)   When you assign a fact table to a subject area,the fact table’s related tables are automatically assigned to the subject area.

3)    If you determine you do not need one or more of the related tables, you can remove the tables during the subject area Assembly process.

4)   This kind of modification is referred to as pruning the subject area.

5)    You can also add individual tables and tasks.

6)   To preview a subject area, follow the procedure "Creating a Subject Area" through the assembly and review stages, but do not complete the process (by clicking Accept in theSubject Area Assembly dialog box) unless the subject area is suitable for your needs.

How DAC Determines Tasks Required for Subject Areas

A subject area is a collection of tasks.

When a subject area is defined, DAC uses the following logic to assemble the collection of tasks:

1. Initial selection of tables.

Find all the fact tables that belong to the subject areas.

2. Recursive selection of related tables.

Recursively find all the tables directly related through foreign keys and all other logically related tables.

3. Initial selection of tasks.

Find all the tasks that load into the tables selected above, that is, tasks whose

target tables are one of the tables identified above.

Tasks that DAC automatically assigns to a subject area are indicated with the

Autogenerated flag (in the Tasks subtab of the Subject Areas tab).

You can inactivate a task from participating in a subject area by selecting the

Inactive check box (in the Tasks subtab of the Subject Areas tab).

When the Note: To change a preconfigured subject area or to create a new

subject area, you must first make a copy of an existing source system

container or create a new container. For instructions, see "Creating or

Copying a Source System Container".

Creating a Subject Area

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Inactive check box is selected, the task remains inactive even if you reassemble the subject area.

You can also remove a task from a subject area using the Add/Remove command in the Tasks subtab of the subject Areas tab, but when you remove a task it is only removed from the subject area until you reassemble the subject area.

4. Recursive selection of all tasks.

Depending on the source and target table relationships, recursively figure out the

prerequisite tasks.