Union transformation in Informatica

What is Union Transformation ??

• A Union transformation has multiple input groups and one output group.
• Union transformation. equivalent to UNION ALL in SQL
• Union transformation does not remove duplicate rows
• Output and input ports can be created manually or passed from another transformation
• Cannot use a Sequence Generator or Update Strategy transformation upstream from a Union transformation.

Components of Union Transformation

1. Transformation tab: To rename the transformation and give a description.
2. Properties tab: You can specify the tracing level.
3. Groups tab: For creating and removing groups
4. Group Ports tab: For creating and removing ports of groups.

Union Transformation

Things to Remember

• Number of ports in the entire input group should be the same. If you connect all ports in one input group, but do not connect a port in another input group, the Integration Service passes NULLs to the unconnected port.

• When you add a Union transformation to a mapping, you must verify that you connect the same ports in all input groups. If you connect all ports in one input group, but do not connect a port in another input group, the Integration Service passes NULLs to the unconnected port.