HI,

 We use keys to provide relationships between the entities(Tables). By using primary and foreign key relationship, we can maintain integrity of the data.

The natural key is the one coming from the OLTP system.

The surrogate key is the artificial key which we are going to create in the target DW. We can use thease surrogate keys insted of using natural key. In the SCD2 scenarions surrogate keys play a major role

Cheers,

Hanu.