ACCORDING to ORACLE Document:

You define a subject area by specifying a FACT table or set of fact tables to be the central table or tables in the subject area. When a subject area is defined,

DAC performs the following process to determine the relevant tasks:

DAC identifies the dimension tables associated with the facts and adds these tables to the subject area.

DAC identifies the related tables, such as aggregates, associated with the fact or dimension tables and adds them to the subject area definition.

DAC identifies the tasks for which the dimension and fact tables listed in the two processes above are targets tables and adds these tasks into the subject area.

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 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.

DAC identifies the source tables for the tasks identified in the previous process and adds these tables to the subject area.

DAC performs this process recursively until all necessary tasks have been added to the subject area. A task is added to the subject area only once, even if it is associated with several tables in the subject area. DAC then expands or trims the total number of tasks based on the configuration rules, which are defined as configuration TAGS. This process can be resource intensive because DAC loads all of the objects in the source system container into memory before parsing.

According to Oracle Document:

You define a subject area by specifying a fact table or set of fact tables to be the central table or tables in the subject area. When a subject area is defined,

DAC performs the following process to determine the relevant tasks:

DAC identifies the dimension tables associated with the facts and adds these tables to the subject area.

DAC identifies the related tables, such as aggregates, associated with the fact or dimension tables and adds them to the subject area definition.

DAC identifies the tasks for which the dimension and fact tables listed in the two processes above are targets tables and adds these tasks into the subject area.

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 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.

DAC identifies the source tables for the tasks identified in the previous process and adds these tables to the subject area.

DAC performs this process recursively until all necessary tasks have been added to the subject area. A task is added to the subject area only once, even if it is associated with several tables in the subject area. DAC then expands or trims the total number of tasks based on the configuration rules, which are defined as configuration tags. This process can be resource intensive because DAC loads all of the objects in the source system container into memory before parsing.