​@Ayush kumar I would turn to the ONE Desktop app here and build a component rule. Using the Lookup step, you can not only check that the given value matches one of the values in the lookup file, but also capture the specific lookup key value that was found in the file. That is not something you can do in the web app.

In the Lookup step configuration, use the lookup.key expression to store the value into some working column:

From there you could calculate the difference between the src_value and the working column, and decide the VALID/INVALID result based on the outcome.

Does that help?

Thanks for the solution ​@Lisa Kovalskaia. That's quite helpful, just wanted to know how can I make this solution possible, I mean I am having my lookup and catalog item in web version, how can I establish a connection in between web version and desktop version and take my lookup and CI there , it would be great if you can provide any link of ataccama support/help document or link of any related community post.