- Use one Source Qualifier transformation to join data from multiple relational tables. These tables must be accessible from the same instance or database server.
- When a mapping uses related relational sources, you can join both sources in one Source Qualifier transformation. During the session, the source database performs the join before passing data to the Integration Service. This can Increase performance when source tables are indexed.
- Use the Joiner transformation for heterogeneous sources and to join flat files.
- Use the Joiner transformation when you need to join the following types of sources:
- Join data from different source databases
- Join data from different flat file systems
- Join relational sources and flat files