COGNOiSe.com - The IBM Cognos Community

ETL, App Development and other tools => COGNOS DecisionStream/Data Manager => Topic started by: S2000 on 15 Jun 2011 07:40:25 AM

Title: SCD, no tracking box ticked, new records created
Post by: S2000 on 15 Jun 2011 07:40:25 AM
I've encountered an odd situation in a legacy dimension built several years ago by a person who's long since left.
It's in Decision Stream.

The dimension is set to be an SCD, but not of the rows have the tracking box ticked.
As far as I understand it this should mean the columns are all subject to a type 1 change, which is to say the attributes are updated based on the bkey.

However, the table seems to have multiple records for the same bkey with SCD dates and Curr_ind, but all the data on each row seems to be identical.

Can anyone shed any light on this please?
Title: Re: SCD, no tracking box ticked, new records created
Post by: bdouglas on 15 Jun 2011 11:15:38 AM
A type 1 change will overwrite all previous records.  If a dimension was previously type 2 with multiple records per business key and you change all the fields to type 1 all it has done is overwritten the history of the dimension and made every record for the business key the same, it will not go back and "merge" records.
Title: Re: SCD, no tracking box ticked, new records created
Post by: MFGF on 17 Jun 2011 11:08:10 AM
Yep - agreed.  This sounds like Type 2 behaviour was previously selected by having at least one track box checked, and history started to accumulate for a while, then the box was unchecked at a later date and Type 1 changes have updated all the history rows for the bkey.

I don't see how else you could have arrived at this situation in the data.

Regards,

MF.