the CUSTFAC table links Customers and Inventory.
truncate SFCxxx_HDW (where xxx is 001, 002 e.t.c.)
The SQL statement below will show what tables contain references to Inventory:
SELECT HDWTABLEID, HDWELEMTID
WHERE HDWELEMTID LIKE '%FACL%'
Set the fields to NULL in each of the tables that are returned by the SQL statement that do not appear in the previous truncate statements
ie: update CALL_HDW set FACLSRN_HDW = NULL, FACLTID_HDW = NULL, LASTFACLSRN_HDW = NULL, LASTFACLID_HDW = NULL