topic Re: DB2 UNIQUE pseudo column in Talend Studio

DB2 UNIQUE pseudo column

Anonymous — Tue, 06 Feb 2018 12:11:48 GMT

Hello

In one of the DB2Input components, the SELECT statement uses a pseudo columns called ‘UNIQUE’

"SELECT

WF.UNIQUE

FROM "+context.BDU_DB2_Schema_BDU+".WATCHFOLDER WF

INNER JOIN "+context.BDU_DB2_Schema_BDU+".WATCHPATTERN P ON WF.ID = P.WATCHFOLDER_ID

WHERE P.ID = "+context.patternID

I am trying to find out what this is and so far online search is not yielding anything useful.

I am guessing that the ‘unique’ pseudo column retrieves the number of unique rows based on a number of non-unique columns that taken together may constitute a unique value (i.e. composite key), but clearly the above SQL does not suggest that.

When I attempt to execute the above SQL using SquirreL connected to DB2 DB, I get 5 rows of zeros.

Does anyone know what does this UNIQUE column supposed to do ?

Appreciate your help

Thanks

Patrice

Re: DB2 UNIQUE pseudo column

TRF — Tue, 06 Feb 2018 12:25:52 GMT

Hi,
Is UNIQUE present when you ask for a desc of the table WATCHFOLDER?
If so this not a pseudo-column.
Else you should get the answer from the DB2 documentation.

Re: DB2 UNIQUE pseudo column

Anonymous — Tue, 06 Feb 2018 12:30:24 GMT

Thanks. You were absolutely right. I have been a bozo. 'UNIQUE' is actually a column in the table rather then a pseudo column.

I have been staring at this SQL way to long to notice, the explanation is much simpler.

Thanks very much.

Patrice