Abstract: A database co-processor for efficient sequential data retrieval from a relational database is provided which is adapted for connection to a host system via a two-way bus network. The database co-processor includes an interface unit connected to receive and transmit data over the two-way bus network, and a database engine connected to the interface unit by input and output buses. The database engine includes a relevant field selection unit for storing selection criteria relevant to a database query raised by the host system processor. A comparator, which is incorporated into the database engine, compares input candidate data received on the input bus in accordance with the selection criteria and produces a result. The database engine further includes memory for the storage of output candidate data received on the input bus.

Abstract: A database co-processor for efficient sequential data retrieval from a relational database is provided which is adapted for connection to a host system via a two-way bus. The database co-processor includes an interface unit connected to receive and transmit data over the two-way bus and a database engine connected to the interface unit by input and output bus means. The database engine includes a relevant field selection unit for storing selection criteria relevant to a database query raised by the processor. A comparator which is incorporated into the database engine compares input candidate data received on the input bus in accordance with the selection criteria and produces a result. The database engine further includes a storage medium for the storage of output candidate data received on the input bus.

Abstract: A summation unit device suitable for the cumulative summation of integer and/or floating point format data presented to an input thereof. The device is particularly useful as an adjunct to a relational database co-processor, receiving data therefrom relating to a plurality of different columns of a database table for the independent summation of the different columns. The data is received on a byte-by-byte basis, and summation takes place in "quasi-realtime" on each byte as it is presented at the device input. A number of running totals are generated which may be output at the end of the database query. The device uses a register for storing a plurality of running totals, a byte-adder for summing each new data-byte with a respective byte from the running totals register, and byte- and bit-shifting operations to correctly align floating point mantissa during summation in accordance with an exponent difference value determined from the respective running total and new floating point format data.