Abstract: A system and method for identifying a selection of index candidates for a relational database. The system includes a Predicate Analyzer for examining database queries in workload and recording column and predicate information; a Search Engine for performing a combinatorial search of index candidates; an Index Emulator for emulating the existence of a set of candidate indexes by making necessary “fake” entries into the relational database management system data dictionary; and a Query Optimizer for estimating the cost of a given query within a given index configuration. In accordance with the method, data indicative of a workload comprising one or more queries is received, and predicates are then analysed and organized into column groups for each basic predicate type. Statistics are collected on each of these groups. Non-predicate portions of each query are scanned to obtain additional covering columns. A combinational search is performed on the column groups to identify covering and non-covering candidates.

Abstract: A merchant who operates a physical store is able to communicate a message to a customer who is carrying one or more items for purchase. While the customer is moving through the store, the merchant uses electronic means to gather data identifying at least one of the items carried by the customer. A computer-implemented program applied to the data analyzes the data and identifies at least one alternative item that the customer might want to buy. The program then prepares a message about the alternative item and delivers the message to the customer while the customer is still in the store.

Abstract: A merchant in a virtual retail store uses a computer-implemented technique to communicate a message to a customer who has selected multiple items for purchase. On establishing an online shopping session with the customer, the merchant's system maintains a list of the items that the customer has selected for purchase during the session. The system provides information about these items to an analytical program, which in turn identifies at least one alternative item that the customer might want to buy. The system then prepares a message that includes information about the alternative item and, before the online shopping session has ended, delivers the message to the customer.