BENTONVILLE, Ark. -- Wal-Mart Stores has promoted Robert DiPiazza to the position of senior vice president and general merchandise manager for its Sam's Club division, in recognition of his six years of service. DiPiazza, most recently vice president and general merchandise manager, will be responsible for all aspects of the refrigerated, frozen and fresh-foods categories for 538 Sam's Club locations around the country. He joined the company in 1998, and prior to that, held various positions at Dominick's Finer Foods, Chicago. DiPiazza, who reports to Doug McMillon, executive vice president, Sam's Club merchandise, has served on the board of directors of the Produce Marketing Association and is an active member of the Food Marketing Institute.