Thursday, April 11, 2019

Union Transformation

Union Transformation is Connected and Active transformation. 
It is used when we have requirement like multiple input groups but only 1 output group. It is used to merge data from multiple sources and load into single target. So this types of transformation is called multi input group transformation.

We cannot use a Sequence Generator or Update Strategy transformation upstream from a Union transformation

Union transformation is similar to the Union All in Sql. 
So it does not remove duplicates just like the Union All from Sql.

Steps to create a union transformation :-
- Go the mapping designer, create a new mapping or open an existing mapping
- Go to the toolbar-> click on Transformations->Create
- Select the union transformation and enter the name. Now click on Done and then click on OK.
- Go to the Groups Tab and then add a group for each source you want to merge
- Go to the Group Ports Tab and add the ports.






No comments:

Post a Comment

SUBQUERIES PRACTISE QUESTIONS

1. Write a SQL query to find those employees who receive a higher salary than the employee with ID 7369. SELECT * FROM EMP WHERE SAL >  (...