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aggrigates

Former Member
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87

could any one help me

how to create flat aggrigate?

what is the importence of flat aggrigate?

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Answers (3)

Answers (3)

Former Member
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Flat-Aggregates-

If there are less than or equal to 16 characteristics in the aggregate, the dimensions will be saved as line items. These are so-called “flat aggregates”. If there are more than 16 characteristics in the aggregate then the dimension will be created accordingly to the dimensions of the basis cube!

Hope it helps

Chetan

@CP..

Former Member
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Hi,

we know that aggregates are baby cubes ie they will contain fact tables and dimension tables.

when u use less than or equal to 13 characteristics in aggregate creation then system automatically assign each to one dimension table, so when only one char. is used in dim table system can make it as Line item dimension. remaining 3 dimensions are time, data package and unit.

by this we can improve the performance of aggregate.

this type of aggrgate is called as flat aggregate.

bye.

chemicala_srimallikarjuna
Active Contributor
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hi,

If you create an Aggregate with more than 16 characteristics, then we call that aggregate as FLAT Aggregate

When an aggregate is active then new data is not available for reporting,These aggregates are called Flat Aggregates.

If an aggregate has less than 15 components, BW 3.x puts each component automatically into a separate dimension that will be marked as “line item” (except package and unit dimension); these aggregates are called flat aggregates.

Note : Flat aggregates can be rolled up on DB Server (without loading data into Application Server).

simply said flat aggregate is when each characteristic is put into separate dimension, these dimensions are marked as 'line item' dimension, in other word every dimension has only one characteristic (except the package and unit dimension).

check these links

line item and high cardinality

http://help.sap.com/saphelp_nw04/helpdata/en/a7/d50f395fc8cb7fe10000000a11402f/frameset.htm

Also refer to this thread

*pls assign points,if info is useful*

Regards

CSM reddy

Former Member
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Hi

I got contradiction answers

Is it more than 16 characteristic or less than 16 characteristic

former_member699913
Contributor
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less than or equal to 16

Former Member
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Less than or equal to 16

Hope it Helps

Chetan

@CP..

Former Member
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As other have said, it is less than or equal to 16 chars, although the 16 includes the ones you get automatically (packet and unit) and an aggregate almost always includes a time dim as well, so you really are limited to 13 chars that you select.

A flat aggregate will generally provide better query performance, as the SQL stmt does not have to contain joins to dimension tables; the fact tabel can be joined directly to the SID tables.

When defining aggregates on a cube, you need to include at a minimum, the characteristics that are in the initial view, in any RKFs, and used in global filters. Now if that mimimum required set of chars in the aggregate is 13 or less, then I create that aggregate, and then create other aggregates that contain chars that are frequently filtered or drilled on. of course you should continue to monitor aggregates to see that they are being used - an aggregate that isn't used much probably should be deleted.