In my application there is vendor who comment when submitting a form and when it comes towards reviewer the reviewer comment again.So I want to show it as history what vendor commented and what reviewer commented.
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The comments are supposed to be used on record type views or interfaces on a site?
create another record using the database and name it a comment. Then in the comment record provide mapping to your primary record using a many-to-one relationship. In case you are in your primary record then define the one-to-many relationship. You have to define mapping only at one record. After this every time a comment is written then save it as a new row in the comment record. Use the write to record smart service in the process model.
Now coming to views create a summary view, and comment view. In the comment, view passes the PK of a record as a rule input. Then create read-only grid using a!recorddata(recordtype:comment, filters: query filter (field:"FK",operator:"=",value:ri!ruleinput))
These comments must be used as a view on the record. When creating the primary record grid provide redirection directly to the summary view and comment view. As sites contain only 5 tabs and comments are not your main functionality. Only define those records on separate tabs in the site which is primary/separate functionality unless the business users want to see it on a separate tab.
interfaces on a site
This too is very helpful