Anti-pattern: Using a HASHKEY to generate the LINK HASHKEY

Link Hashkeys should be generated using the Business Keys participating in the Link, and not the Hashkeys of of the Hubs. 

Hashing a hash is just bad design.

Anti-pattern: Excluding the Dependent Child in the generating the LINK Hashkey

If your LINKs have Dependent Childs, for e.g. Order Line Item as show below, it is crucial that the Order Line Item is included the LINK Hashkey.

If the Dependent Child is not included the generation of the LINK Hashkey, the JOINs to the LINK table will not be easy.