02-12-2014 05:31 AM
Thanks for your reply. This is just for my learning with SCD Type 2 Loader.
As we know - For efficiency, cross reference tables are used during updated of dimension tables by the following transformations :
SCD Type 2, Key Effective date, lookup...
While learning for cross reference table - I got the word MD5 Algorithm.
Uma Shanker Saini
02-12-2014 06:14 AM
Well, all I can tell you it seems that the SCD uses this as a standardized way to do comparisons between source data and the corresponning valid row in the dimension table.
I belive for dimensin with long records it could be better performance. either way, it simplifies the coding in the comparison step, the alternative would be somthing like
case a.name <> b.name
or a.age <> b.age or