OWB trying to create merge when should be update statement

Question

Hi there
Have a problem whereby when set target update type of table to update, OWB trying to create a merge and failing with message merge sttament cannot be generated because column <column_name> is used for both matching and update.
A matching column cannot be updated in a merge statement.
We are trying to only update certain rows in a target table.
What is the best way to do this in a mapping in normal sql we
would do
update table
set cola = 12, col b=14
where cola = 10
Many Thanks

Answer 1

Hi there
Thanks for this. I get your idea of doing filter on target at start.
However in our situation I'm not certain how to achieve what we require, being new to OWB.
We have a source staging table with various tranasctions (updates, inserts and deletes all flagged with a timestamp. We need to process these as follows:
1) Inserts become inserts on the target table
2) Deletes become updates on target table, expiration date set to timestamp of record on source table. Here we need to limit the update to only update open record thus not changing history for the code concerned. Open record identified as expiration date set to '31/12/4000'
3) Updates become Updates, setting expiration date on current record to timestamp of staging table record, again only updating currently open record which is identified by expiration date set to '31/12/4000'.
What I thought of doing would be mapping
starting with target table going into a filter to get open records '31/12/4000'. This with joiner operator to staging table and the results of joiner to target table load type set to update. This would handle deletes and the update part of updates.
However this wouldn't take care of the inserts and the second part of updates, i.e. the requirement to insert new record to cater for the update.
Thought about two mappings, one with target type of update as above and another for inserts, but problem would be need to process all records in staging table in right order, e.g in one day could have insert then update. Couldn't run insert mapping first as update mapping would then run and close off the inserted record.
Basically looking for advice on best way to achieve the above.
Many Thanks