Note: This source should be combined with other sources at this level (check box) Description: Check this box when data sources at the same level of aggregation do not contain overlapping information. In this situation, all sources must be combined to get a complete picture of information at this level of aggregation.
Note 2: To use a source correctly, the Analytics Server has to know what each source contains in terms of the business model. Therefore, you need to define aggregation content for each logical table source of a fact table.
The aggregation content rule defines at what level of granularity the data is stored in this fact table.
Use the Content tab of the Logical Table Source dialog box to define any aggregate table content definitions, fragmented table definitions for the source, and Where clauses (if you want to limit the number of rows returned).

CurrentMonth can be calculated by a sql statement.
Note:
REPOSITORY VARIABLE(DYNAMIC)
Initialized when BI server is started
Assigned value dynamically based on the result of a query
Value is dependent of the sql provided in Initialization Block
Create a dynamic variable and provide a Name and Default Initializer.Create a new initialization block by clicking on the New button in the above screen.

Provide Intialization Block variable Name

Click on "Edit Data Source" button and provide the sql to be used for the variable, e.g.
select lower(sys_context('USERENV','SESSION_USER'))||
'@'||
lower(sys_context('USERENV','DB_NAME'))
from dual;

You can specify a Driving table parameter in a complex join.
Driving tables are for use in optimizing the manner in which the Oracle BI Server processes cross-database joins when one table is very small and the other table is very large.
The BI Server will query the driving table (the small one) and will get a list of values. The BI Server will then generate a second SQL using a parameterized IN list with the values from the first query.
Specifying driving tables leads to query optimization only when the number of rows being selected from the driving table is much smaller than the number of rows in the table to which it is being joined.

A single query can be performed accessing data from both tables through a join on the columns in the foreign key relation.