Informatica - Union Transformation

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Union Transformation

Why Union transformation is active while it returns same number of rows as in the sources?

Total Answers and Comments: 5

Last Update: March 01, 2009 Asked by: saurabh7385

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Submitted by: nandu214

But union transformation doesn't delete the duplicate records when we are joining two tables i found this information in Informatica help.

can anyone throw light on this.

Above answer was rated as good by the following members:
chvamshy, DK_Reddy

April 04, 2008 04:43:54

suvomoy.chakraborty@patni.com

Member Since: April 2006 Contribution: 1

RE: Union Transformation

Union Transformation in general does not allow duplicate rows. If the sources contain duplicate rows then the effective count of rows after union certainly will be reduced. That should be one of the reasons for it being an active transformation.

A question may be raised regarding a situation where the sources do not contain any duplicates. The answer should be even in that scenario the transformation's inherent ability to check for the duplicate rows will remain intact. Just like a filter transformation not changing the row count because the filter condition was not either entirely true or entirely false for all of the rows.

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June 22, 2008 05:52:27

nandu214

Member Since: June 2008 Contribution: 6

RE: Union Transformation

But union transformation doesn't delete the duplicate records when we are joining two tables i found this information in Informatica help.

can anyone throw light on this.

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Overall Rating: +2

July 09, 2008 07:09:00

Rashmirekha

Member Since: November 2007 Contribution: 6

RE: Union Transformation

Hi

Please make a note that there is no option available in a Union transformation to handle duplicates.It does a 'UNION ALL'. If handling of duplicates is the requirement then Sorter can be used.

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January 08, 2009 04:49:50

gaurav2485

Member Since: January 2009 Contribution: 12

RE: Union Transformation

Suppose we have 2 Source with 100 & 200 rows then output will be 300 rows so I/p O/p rows number vhange that is Active transformation

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0 3

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February 27, 2009 05:53:26

chvamshy

Member Since: December 2008 Contribution: 1

RE: Union Transformation

Union Transformation is active because you configure a session using update strategy the session property data driven instructs informatica server to use the instructions coded in mapping to flag the rows for insert update delete this is the default option selected when using a update strategy transformation in a mapping.

Union transformation is developed using the Multigroup External Procedure transformation which is an active transformation.

Regards
Vamshi Cheedella

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