SCD2 implementation

[devika]

Hi Experts,

I am new to BODS,I would like to know if SCD2 can be implemented in a dataflow without using History preserving transform.My TL says using History Preserving Transform in the dataflow will be a bottle neck when the source is having huge volumes of data.Any alternatives for History Preserving Transform.Please advise.

Thanks in advance

[reddevilme]

What kind of volume are we talking about here?

There are ways to implement SCD2 without using History_Preserving transform but I am not sure if they would be as efficient.

Instead of using History_Preserving, you can make the updates from Table Comparison (or lookup if you do not plan to compare any columns) as inserts. You can use the same updates to expire the existing records in the target using the Pk/Surrogate Key that you get from TC. You might need to use Transaction control in such cases to avoid table locks.

[eganjp]

I wouldn't expect the History Preserving transform to add that much overhead. It is not a database operation. Meaning that it doesn't query the database. All it does is turn updates into updates and inserts. That's greatly simplifying what it does but it doesn't really do much.