How is the merge done in DataStage?

Here are some necessary steps to set up a Merge in Datastage:

• Go to the Stage page Properties Tab
• Now, specify the key column or columns to be merged
• Inside the Stage page Properties Tab, you need to set the Unmatched Masters Mode, Warn on Reject Updates, in addition to setting the Warn on Unmatched Masters options or accept the defaults.
• After that, in the Stage page Link Ordering Tab, you need to check if your input links are correctly identified as "master" and "update(s)," and the output links are defined as "master" and "update reject."
• Most importantly, you need to ensure the required column metadata is specified
• Finally, go to the Output Page Mapping Tab and specify the order of mapping the columns from the input links map to the output columns.