Alternate Part Number

This code must be unique across different parts, but must be the same for the same part across different plants.  If the part does exist in other plants, then the alternate part number will default to the screen and will be protected during add mode.  If the part does not exist in any other plants, then the alternate part number will be enterable and will be validated for uniqueness.  If part copy is used to create the part in a different plant, then the alternate part number will be copied as well.