Simple Upsert example. No deleted source records, no changes to key.
Initial Load Upsert
Target Table After Initial Load Upsert
(4 rows loaded)
2nd Load Upsert
The first step of the upsert process extracts the highwater mark from the target table. In this example the highwater mark is before the from Sequence column in target table before Upsert is
Before: The highwater mark is
104. (See Sequence column in Target Table after step above)
Target Table After 2nd Upsert
(2 rows upserted)
Target Table in Database
Included for those interested. Very few users need to know the internals of the database tables storing the data warehouse.