Archive for February, 2007

Type II dimension: What is expiry date? Does it come from Source or is it ETL date?

Tuesday, February 6th, 2007

I assume everyone is aware of type II dimension concept.  In type II dimension when we get an updated row we retire old row and insert new one. But what do you populate  in the from_date —to_date attributes. ETL create/update datetime or when that particular row was retired in the source system?

The question can be asked in a different way… When a employee changes from one department  to another department; While populating in the data warehouse type II dimension EMPLOYEE table… Do you use the actual date of his transfer or the ETL date when you are populating the table?

What are you doing in your ETL code?