Taking the sorted data

[fmou]

Hi,

It is recommended to use the "same" method when the data is sorted in previous stages, however, I'm wondering what if the previous stage is a database stage, that sorts data using the "order by" sql clause.

Can I still use the "same"sorting method?

thanks

[asorrell]

That's a great question...

If the sort is done by the database (ie: an ORDER BY clause) then DataStage doesn't have visibility to the keys, so "SAME" doesn't quite cover it.

What you should do is insert a SORT stage after the database stage and mark all the keys (and sorting orders) on the stage. Then change all the Sort Key Modes to "Don't Sort - Previously Sorted". This makes sure that DataStage has the required information but won't attempt to resort the data. Any stages after that can use the "Same" option safely.

[fmou]

Again, exactly the answers that I was looking for! Thanks a lot.

One more question to make it complete, if I use " Don't Sort - Previously Sorted ", will the "key field changed", "group changed" DS fields get popIulated correctly? If no, I do have to "re-sort" it in DS, right?

Thanks

[ray.wurlod]

The generated fields will be populated correctly provided you have not lied about the "already sorted/grouped" assertion.