The main information for an item master (Internal part) is contained in the INVENTOR table.  For every AVL that is added to the part, a record is created in the INVTMFHD table.  The AVL is linked to the item master by the field Uniq_key in each table.  When an inventory warehouse/location is added to an AVL, another record is added to the INVTMFGR table.  The Warehouse information is linked to the AVL information by the Uniqmfgrhd field.

When a User adds a customer part number to an item master (internal part), an additional record is added to the INVENTOR table.  This record contains the same information as the internal part, but with a DIFFERENT Uniq_key, and is identified with a Part_sourc field as CONSG, and includes the customer part number and revision.  This additional record is used both for consigned information and to identify the customer part number by customer.  It is linked to the internal part through the Int_uniq field, which contains the internal uniq_key associated with the customer part.  When the customer part number is added, the AVLs and Locations are also duplicated in the INVTMFHD and INVTMFGR tables, in the same linking as described for the internal parts.

When a supplier part number is added to the table INVTMFSP.  There the supplier information is contained as well as the supplier part number.  Because it is linked specific to an AVL, it is linked by the Uniqmfgrhd field to the INVTMFHD table, in similar fashion as the INVTMFGR table.

Diagrammatically, it could be described as:

INVENTOR  . . . . . . . . . . . . . . . . .  Item Master
       INVTMFHD . . . . . . . . . . . . . . . . . Manufacture information
             INVTMFGR . . . . . . . . . . . . . . . .  Warehouse information
             INVTMFSP . . . . . . . . . . . . . . . .  Supplier information

So there will be one set of these for every internal part number, and may be multiple sets of the same information for different customer part numbers.