Apparatus and method for transparent access of foreign databases in a heterogeneous database system

A method for processing a statement from a client, comprising the steps of:

• receiving the statement at a local database system, said statement specifying a plurality of operations that need to be performed to execute the statement;
• identifying at least one of the operations specified by the statement to be performed by a foreign database system, wherein said at least one of the operations includes an access to metadata in a structure supported by the local database system and not supported by the foreign database system;
• converting the statement specifying said at least one of the operations to be performed by a foreign database system into a request based on stored data describing data dictionary translations for the foreign database system;
• and
• sending the request from the local server process to the foreign database system to perform said at least one of the operations for processing of the statement, wherein the request includes an access to metadata in a structure supported by the foreign database system.

A computer-readable medium having stored thereon sequences of instructions for responding to a request for performance of an operation received by a local server process, the sequences of instructions including instructions for performing the steps of:

• receiving the statement at a local database system, said statement specifying a plurality of operations that need to be performed to execute the statement;
• identifying at least one of the operations specified by the statement to be performed by a foreign database system, wherein said at least one of the operations includes an access to metadata in a structure supported by the local database system and not supported by the foreign database system;
• generating a request for the foreign database system to perform said at least one of the operations based on the statement specifying said at least one operation, wherein the request includes an access to metadata in a structure supported by the foreign database system;
• and
• sending the request to the foreign database system to perform said at least one of the operations.

A computer-readable medium having stored thereon sequences of instructions for responding to a request for performance of an operation received by a server, the sequences of instructions including instructions for performing the steps of:

• receiving the statement at a local database system, said statement specifying a plurality of operations that need to be performed to execute the statement;
• identifying at least one of the operations specified by the statement to be performed by a foreign database system, wherein said at least one of the operations includes an access to metadata in a structure supported by the local database system and not supported by the foreign database system;
• converting the statement specifying said at least one of the operations to be performed by a foreign database system into a request based on stored data describing data dictionary translations for the foreign database system;
• and
• sending the request from the local server process to the foreign database system to perform said at least one of the operations for processing of the statement, wherein the request includes an access to metadata in a structure supported by the foreign database system.

A computer system configured to respond to a statement, comprising:

• a computer-readable medium storing a data dictionary that includes a data dictionary translation table specifying mapping information on how to map from a local data dictionary table to a foreign data dictionary table of a foreign database system;
• and
• a local server process configured for receiving the statement from the client and determining operations necessary for execution of the statement,
• wherein the local server process includes a heterogeneous services module configured for:
• identifying at least one of said operations specified by the statement to be performed by a foreign database system, wherein said at least one of the operations includes an access to metadata in a structure supported by the local server process and not supported by the foreign database system;
• converting the statement specifying said at least one of the operations to be performed by a foreign database system into an operation request based on stored data describing data dictionary translations for the foreign database system;
• and
• sending the operation request to the foreign database system to said at least one of the operations, wherein the operation request includes an access to metadata in a structure supported by the foreign database system.