If the source data uses a surrogate key, the warehouse must keep track of it even though it is never used in queries or reports; it is done by creating a lookup table that contains the warehouse surrogate key and the originating key.
The warehouse must keep track of it. It is never used in queries or reports. The source data uses a surrogate key. It is done by creating a lookup table. This lookup table contains the warehouse surrogate key. This lookup table contains the originating key.