Apparatus and method for accessing foreign databases in a heterogeneous database system

摘要

An apparatus and method for accessing foreign processes in a heterogeneous database environment includes a local database server having a heterogeneous services module to selectively send requests to the foreign processes based on their respective capabilities. A client application sending a statement to the local database server is checked by the local server process to determine if the statement includes a reference to a foreign database system, or whether the statement is registered as an external routine. The heterogeneous services module selectively outputs a request to an agent process executing in an address space separate from the local server process and in communication with the foreign database. The agent process performs all necessary interaction with the foreign database, including data type translation. The agent includes a conversion module that includes data type conversion routines, and which may obtain additional conversion routines via an Application Programming Interface (API) from a foreign database driver corresponding to the foreign database. The converted request is output from the agent process to the foreign database. Hence, the heterogeneous services module manages client statements involving foreign database systems having limited capabilities, as well as client statements having expressions unrecognizable by the local database server. Use of the agent process ensures that the integrity of the local server process is protected.