first() implemation in datastage

chvenkat.v · Post by **chvenkat.v** » Wed Aug 19, 2009 7:48 am

I wants to implement first() function in datastage. As you know we have first function in aggre trfm stage in informatica . In my case we are getting the values from source seq. file, and it is a migration from informatica to datastage. So, we need to replace same logic in PX job. Please tell me how to implement this.

Thanks!
venkat.

miwinter · Post by **miwinter** » Wed Aug 19, 2009 7:57 am

As a Datastage forum, members here are not likely to necessarily know anything about Informatica. I have used it previously, albeit some 7-8 years ago now, yet even I can't recall what the first function does.

If you explain what it is you need to achieve, forgetting all about Informatica, it would be far simpler for anyone to answer your query. I'd guess, from the fact you are using it in an aggregation, that it's some kind of min/max function though (i.e. keep first).

ArndW · Post by **ArndW** » Wed Aug 19, 2009 8:03 am

DataStage also has an aggregator stage with similar functionality. Have you tried using that?

Sainath.Srinivasan · Post by **Sainath.Srinivasan** » Wed Aug 19, 2009 8:03 am

It is available in DS Server edition.

In PX, you can use a tx or lookup first row.

chulett · Post by **chulett** » Wed Aug 19, 2009 8:14 am

Group change detection using stage variables in a transformer, constrain to only the first element in each group.

[first answer was more min() than first() unfortunately]

ray.wurlod · Post by **ray.wurlod** » Wed Aug 19, 2009 6:29 pm

Remove Duplicates stage is the easiest way to capture the first record of each group.

As noted, the keyChange column that can be generated by a Sort stage can also be used to flag the first record in each group.