Simple question..or not!

Question

Hi gurus.
I have a simple question to do!!
In my ETL map I need to create the follow rule.
ERP Table to DW table:
- if ERP table primary key = DW table primary Key then execute the UPDATE command in DW --> THIS IS OK!
- if ERP table primary key <> DW table primary Key then execute the INSERT command in DW and insert the value 'ACTIVE' in status column. --> THIS IS OK!
DW table to ERP table:
- if DW table primary key <> ERP table primary key then execute the UPDATE command in DW and insert the value 'INACTIVE' in status column.
- if DW table primary key = ERP table primary key then ignore.
Somebody knows how can I do this?
Thanks in advanced.
Bruno

Answer 1

In my experience MINUS works just fine in this type of scenario where you are comparing two key columns from two tables. You should make sure that both columns are indexed, and that the mapping is running "set based". In this scenario the CBO will do two index sorts and a minus operation to compare the sorted indexes.
I agree that other methods, like using an outer join and filter, or a "not exists" subquery probably are faster in many cases but if performance is not a real issue, I prefer using minus due to (what I perceive as) better readability of the mapping
Roald