An import set stages incoming data before it reaches a target table. A transform map connects source columns to target fields and defines how to identify existing target records. Coalesce uses selected fields to find a matching record for update; a nonmatching key can create a new record.
Choose a stable identifier. Asset names and descriptions are often duplicated or edited. A serial number can work for this fictional source because its contract makes it unique. Trim leading and trailing whitespace before comparing keys. A blank key needs an explicit reject or ignore policy so unrelated records cannot collapse into one blank identity. Test repeated imports as well as the first run. A map that succeeds once can still create duplicates every morning if identity matching is wrong.