Can we add an info object and its nav. attr in an aggregate together?

Question

Hello
I am getting an error when I try to add 0MATERIAL and 0MATERIAL_OPROD_HIER in an aggregate at the same time. In the cube, both 0MATERIAL and its attr 0MATERIAL_0PROD_HIER sit in the same dimension. Therefore, when I try to create an aggregate and drag these chars in, they try to come into the same dimension here also.
1st scenario:
1. I  add 0MATERIAL in the aggregate.
2. I try to add 0MATERIAL_0PROD_HIER in the aggreate, I get an error message ' Aggregation levels cannot be defined for 0MATERIAL_0PROD_HIER.
3. And it does not let me add this nav attr at all.
2nd scenario:
1. I first add 0MATERIAL_0PROD_HIER in the aggregate.
2. I try to add 0MATERIAL now.. I get the same error as above for 0MATERIAL this time.
3. But it lets me add 0MATERIAL inside.
4. Now, when I go its context menu (right click) and select aggregation as 'All Char Values' for 0MATERIAL, then the error goes away.
5. But after I activate and fill the aggregate, I have a look it again.. and now I only see 0MATERIAL and its nav attr which I added first has disappeared.
Why do the above 2 happen? And if I have an info object and its nav attr in ROWS in a query, and if I am not able to add both of them to the aggregate.. how can I improve the performance of the query?
Please advise.

Answer 1

Hi Srinivas
In your scenario, it is sufficient if you just add 0Material when you are creating the aggregate. Need not add the nvaigational attribute in the aggregate definition. The procedure you followed the first time is right i.e. Drag and drop 0material first.
The system does not allow you to add the nav attribute because it is not required. I say this because a navigational attribute added to your infoprovider is like (in terms of SQL) joining your infoprovider with your material master table. Navigational attribute's value is not physically stored in your cube. It is brought in during execution time in both list cube as well as in your query output.
Similarly when you execute your query with 0material as your aggregate, even if you add a filter or variable restriction on 0Material_prodHier your query WILL use the aggregate since 0material is referenced.
You can even check this in RSRT. Give your query name, and generate report first. Then click on Execute + Debug, Choose Display SQL/BIA Query and enter your selection and choose enter. You will see the SQL of your query and in the SQL select statement you will see that your aggregate table is chosen instead of your infocube. This aggregate table only will be read during your query execution in Bex as well.
I hope this helps.
Thanks.