As I understand you can map one table to an other using the foreign-key / primary-key relationship. I have a slightly different scenario because of a legacy AS400 Database.

Table A has a column C, which can be used to map to the primary key of Table B. However, columnC can't be used as is. Only two digits of the value in ColumnC(TableA) maps to the PK of TableB. I was wondering how to create a mapping <one-to-one> (OR) <one-to-many> in the above scenario.

Any thoughts are greatly appreciated. Thanks.