APPARATUS AND METHOD FOR CALLING EXTERNAL ROUTINES IN A DATABASE SYSTEM

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 for a registered external routine executable by an agent process in an address space separate from the local server process. The heterogeneous services module selectively initiates a network connection with an external agent process, and the external agent process executes the external routine by accessing a dynamically linked library. If necessary, the local database server and the agent process exchange callback queries and callback results via the heterogeneous services module to complete intermediate queries within the same user instance. The local database server then completes the client statement based on the results received from the agent process. Use of a link to an external agent process executing in a separate address space enables the local server process to use enhanced external routines written in third generation languages, without risking the local server process to failures in the external routines.