Abstract: Time-referenced data are pervasive in most real-world databases. Recent advances in temporal query languages show that such database applications may benefit substantially from built-in temporal support in the DBMS. To achieve this, temporal query optimization and evaluation mechanisms must be provided, either within the DBMS proper or as a source level translation from temporal queries to conventional SQL. This invention proposes a new approach: using a middleware component on top of a conventional DBMS. This component accepts temporal SQL statements and produces a corresponding query plan consisting of algebraic as well as regular SQL parts. The algebraic parts are processed by the middleware, while the SQL parts are processed by the DBMS. The middleware uses performance feedback from the DBMS to adapt its partitioning of subsequent queries into middleware and DBMS parts.

Abstract: A method of soldering component leads to I/O pads on a printed circuit board, without desoldering any other circuit components which were previously soldered to the board near the pads, includes the steps of: forming a mechanical assembly in which respective joints of the pads and the leads and respective solder mounds are mechanically held together; moving the assembly at a predetermined speed on a conveyor such that the joints, but not the previously soldered components, sequentially pass through a target area which is small relative to the total number of joints; and melting and then hardening the solder mounds, without desoldering the previously soldered components, by directing a focused stream of hot gas at the target area as the joints move therethrough on the conveyor.