I am trying to break a large data set that contains purchase information into a dimensional model. I have various attributes related to the Item purchased. I do have an Item Number but it is not unique across different manufacturers. The Item is unique by MFR_ID and Item_ID. I have a Manufacturer dimension that contains a MFR_ID and MFR_NAME.
In my Item dimension, would it be best to include both these fields as separate attributes in this dimension or should I concatenate them to create one unique item identifier?