COGNOiSe.com - The IBM Cognos Community

ETL, App Development and other tools => COGNOS DecisionStream/Data Manager => Topic started by: camboo on 03 Dec 2013 07:21:23 AM

Title: DM slowly changing dimension / type 1 and 2 changes for the same record?
Post by: camboo on 03 Dec 2013 07:21:23 AM
Hello,

When slowly changing dimension option is used in Data Manager and there are both type 1 and type 2 changes specified for one table, the following may happen based on Data Manager v10.1 documentation:

"Where type 1 and type 2 changes have occurred for the same record, the type 1 updates that are not marked as type 2 are applied to all records for the business key at the level for which the type 1 attribute is declared, regardless of whether the record is current or no"

However, does Data Manager provide any way to apply those type 1 changes to current record only, not to all records?
Title: Re: DM slowly changing dimension / type 1 and 2 changes for the same record?
Post by: camboo on 04 Dec 2013 06:23:39 AM
Hi,

Can anyone help with this?

There is need to apply type 1 changes to current record only, not to all ones...
Title: Re: DM slowly changing dimension / type 1 and 2 changes for the same record?
Post by: MFGF on 11 Dec 2013 10:36:07 AM
Hi,

A Type 1 change means "I don't care about preserving history for this column" so when a change of this type is made, all rows for the business key are updated to reflect the change (ie the current row and all historic rows). This is definitively correct behaviour.
It sounds like you are looking for something of a hybrid - updating a value on the current row only but not on the history rows?

If you go into the properties of your table in your dimension build, you will probably see all non-business-key columns are marked as either "1" or "2" as the "Track" value. You can also change this to "0" which, I think, is what you need here. Type Zero in Data Manager is for "corrective changes" where the current row needs to be corrected but the history rows should remain intact.

Cheers!

MF.
Title: Re: DM slowly changing dimension / type 1 and 2 changes for the same record?
Post by: camboo on 12 Dec 2013 07:40:47 AM
Hi,

And thanks for the answer!

"updating a value on the current row only but not on the history rows"

--> that is exactly what I'm trying to implement; updating only the current row in case fields "a" or "b" are changing, and on other hand creating a totally new row when fields "c" or "d" are changing. There is no need to make any changes to "history" rows of the business key, in other words type 1 changes.

So, track change type zero could be the solution, I will test that!
Title: Re: DM slowly changing dimension / type 1 and 2 changes for the same record?
Post by: MFGF on 13 Dec 2013 10:53:05 AM
Let us know if it does what you need! From what you're describing I'm pretty sure it will.

Cheers!

MF.
Title: Re: DM slowly changing dimension / type 1 and 2 changes for the same record?
Post by: camboo on 09 Apr 2014 02:43:59 AM
It seems now that it was what I needed! Thanks a lot!  :)