Flat Aggregates

Hello friends,

I searched for Flat Aggregates,i get different answers...

What i understood with SCN.SAP is...

for example we have 1 cube with 4 dimensions like..

Dim1-->>CHAR1,CHAR2,CHAR3

Dim2--->CHAR4,CHAR5,CHAR6

Dim3-->CHAR7,CHAR8,CHAR9

Dim4-->CHAR10( it is a line item dimension)

And now if we create an Aggregate with name AGGR1

AGGR1 -->

Dim1: CHAR1

Dim2: CHAR2

Dim3: CHAR3

Dim10: CHAR10 is this a FLAT AGGREGATE???? If so how many characters can we have in a Flat Aggregate??

Please explain me and pls dont suggest me the SDN links.

Thanks & Regards