What is Update Strategy transformation?

When we design our data warehouse,we need to decide what type of information

to store in targets.As part of our target table design,we need to determine whether

to maintain all the historic data or just the most recent changes.The model we

we choose constitutes our update strategy which tells us how to handle changes to

existing records.

Update strategy flags a record for insert,update,delete or reject.We use this

transformation when we want to exert fine control over updates to a target,based

on certain conditions that we apply.

For eg:When the mailing address of a customer has changed and when we have to

update it we can use update strategy.Also for people no longer working in a

company we can flag all employee records for reject.