When the destination is a memory connection system extracts dataset from the source and stores it in memory. The dataset can be later used to lookup data and update calculated fields, or to parse the response from the web service, or for any other purpose which would typically require storing data in the temporary staging area.
Using in-memory dataset for lookup
Read how to use a lookup when the input a dataset:
Using in-memory dataset to parse the response from the web service
Creating a transformation with a destination set to Memory connection
Step 1. Create a Memory connection.
Step 2. Create any extract-transform-load flow.
Step 4. Set the transformation name.
Step 5. Add other transformations as needed.
var ds = scenario.getSources().get("CAPITALIZED_TRANSFORMATION_NAME").getDataSet();