FLAT AGGREGATES

[Former Member]

HI ALL

Can someone explain about Flat Aggregates and how is that defined.

[Former Member · Accepted solution]

Hi,

Aggregates are represented in the SAP BW system as an aggregate cube.This means that each aggregate consists of two fact tables (E and F) and at

least two dimension tables.But the tecnical construction of the aggregate differs from the basic cube.

While creating an aggregate, when up to fifteen characteristics are transferred into the aggregate,

the SAP BW System creates no "real" dimension. In this case, a line item dimension is created. This refers to

flat aggregates.

check this thread...its good...

[Former Member · Accepted solution]

Hi,

Your cube is organized in dimension with one or several chars per DIM.

If you create an aggregate with only one characteristic of one of the cube dimension, you aggregate dimension will be flagged automatically as Line Item.

A flat aggregate is when all its dimension are line item.

Note that lineitem dimensions doesn't have a transparent table (no storage in DB), therefore the query is reading the fact table directly. It is meant to be faster and usually it is but not always...

ICube
DIM 1: CHAR_A, CHAR_B, CHAR_C
DIM 2: CHAR_D, CHAR_E
DIM 3: CHAR F "flagged or not as LineItem

Flat Aggregate:
DIM1: CHAR_A "flagged LineItem by the system because single char
DIM3: CHAR_F "flagged LineItem by the system because single char

Not flat:
DIM1: CHAR_A, CHAR_B
DIM2: CHAR_D
DIM3: CHAR_F 
Because DIM1 has two chars therefore a DIM table is created.

hope that helps...

Olivier.

[Former Member]

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

Regards

Kiran