In order to successfully implement upsert using Informatica we need to follow these steps:
- In the mapping we need an update strategy with DD_UPDATE before the Target.
- In the session the we need to have the following settings:
- Under Properties:Treat Source rows as Data driven
- Under Mapping, the Target should have both Insert and Update else insert checked.
I do not recommend update else insert for large sets of data if you need a process that is efficient and fast. It is better to stick with having two separates paths in the mapping. One for updates and the other one for Inserts.