Need details where the Change Action code from Change Order Listing Report is stored

Summary: In Change Order Listing Report, we have Change Action code (Add or Update) is mentioned. Need to know where this flag is stored in backend.

Content (required): For an integration we need to know if a line in structure is added (ie a new component is added) or updated (any attribute change ie item quantity update etc). While exploring few options, we came across the change action in change order listing report where its mentions if its 'Add' or 'Update'. Need the details of the table and column where this gets stored so it can be fetched through SQL query in Integration.