The meaning of "automatic" in aggregation function

[ratnalein]

Hallo everyone,

I would like to ask about the meaning of "automatic" for a data element in report studio.  Does it mean, that the column rows always be summarized?  Or does it mean, that report studio will take a look what the column rows are, and will decide by itself?  Thank you..

Regards,

Ratna

[tjohnson3050]

It means that Cognos will decide what aggregation function to use.

[ratnalein]

hallo tjohnson3040,

thank you for the quick reply.  How does Cognos actually decide what aggregation to use?

Regards,
Ratna ;)

[MFGF]

It is set as a default in the Framework Manager model for the item in question.

Cheers!

MF.

[Shivanand]

hi
in Lists Aggregate Function is set to Automatic and it means that depending on the data type aggregation is performed.
following link will explain you for what type of data type what aggregation is done automatically, or what to expect from report studio.
http://publib.boulder.ibm.com/infocenter/c8bi/v8r4m0/index.jsp?topic=/com.ibm.swg.im.cognos.ug_cr_rptstd.8.4.0.doc/ug_cr_rptstd_id10753cr_rptstd_agg_fnctns.html

Your next question how does cognos know what is the data type.
Answer. Cognos report studio determines the data type based on the modelling done at the framework manager level, if data type is not changed at the framework manager level then the original data type from the datasource is passed over.
if the datatype from the data source is not supported by framework manager then it is passed over as unsupported data type.

I hope this answers the question, however this question was quite interesting.

Thanks
Shivanand

[ratnalein]

Hallo MFGF and Shivanand,

thank you guys for the great explanations.  Well, for example in my model:
We take the fact "Number_of_Sales"

In the database view in my framework manager, I model "Number_of_Sales" as follows:
Usage: Fact
Regular Aggregate: Sum
Semi-Aggregate: Sum

In the dimensional view , the model for "Number_of_Sales" is:
Usage: Fact
Regular Aggregate: Automatic
Semi-Aggregate: Sum

In my Report Studio, if I create a data element, which is from the query item "Number_of_Sales":
Aggregate function: Automatic
Roll up Aggregate function: Average

I assume, this is an acceptable constellation.  The Aggregate function can be overwritten from the report author, for example into:
Aggregate function: Sum
Roll up Aggregate function: Average

or

Aggregate function: Count
Roll up Aggregate function: Average

My question:
Sum and Count would overwrite Automatic?

Thank you.

Regards,
Ratna

[Shivanand]

Hi Ratna,

I think yes,
If the author is not specific about the aggregate value he wants, he could leave it to "Automatic".
If Author knows that he wants Count, he could change it to count and "Automatic" would be overwritten/Pushed away.
Likewise, if Author knows that he wants sum/Average or anything else, he could set it so, and "Automatic" would be overwritten.