OBIEE 11g : Implicit Fact Column
An Implicit fact column is used when we have multiple fact tables and the report is getting generated using only dimension columns.
A User may request a report where it may have only Dimensions and no Fact columns. In this case, the server may sometimes get confused as to which fact table should it join to fetch the data. So it joins to the nearest fact table and pulls the data through it. So the report output obtained may be different from what the user is expecting.
So, in order to avoid this kind of error,we need to set Implicit Fact Column.
The goal of this is to guide the BI Server to make the best choice between two possible query paths.
We can set a fact attribute (measure) as an implicit fact column.
We can also create dummy implicit fact column on and assign any numeric value to it.
We can set implicit fact column in presentation catlog properties.
1. Goto properties of presentation catlog in presentation layer.
2. In implicit fact column section click on set and select any measure column from fact table.
3. Click OK.
4. Save your work.
Instead of selecting any fact measure column as implicit fact column, we can also define a dummy implicit fact.
1. Create a Physical Column in Fact table in Physical Layer.
2. Name it as Implicit_Column.
3. Drag this column in Fact table from BMM layer.
4. Double click on logical table source of fact table.
5. In content tab, assign any numeric value to Implicit_Column.
Once this is done we can set this column as Implicit Fact Column in Presentation catlog as mentioned above.