1. At a computer system, the computer system including one or more processors and system memory, the computer system communicatively coupled to an order database for a retailer and to an order database cache, the order database containing order data for a plurality of customer orders, the order database cache containing order data synchronized from the order database, a method for routing an order lookup, the method comprising: receiving an order lookup from a requesting computer system, the order lookup indicating a database command type and indicating a portion of order data associated with a customer order; a processor determining an appropriate data source to service the order lookup based on characteristics of the order lookup, including the indicated database command type and the indicated portion of order data, the appropriate data source selected from among the order database and the order database cache; routing the order lookup to the appropriate data source in response to the determination; receiving the indicated portion of order data back from the appropriate data source, the indicated portion of order data responsive to the lookup request; and returning the indicated portion of order data to the requesting computer system.