The structured query language (SQL) service handles the processing of all SQL-related operations. The work done by the SQL service includes:
Mapping Oracle internal SQL-related calls to the Heterogeneous Services driver application programing interface (API). This API is then mapped by the driver to the client API of the non-Oracle system.
Translating SQL statements from Oracle's SQL dialect to the SQL dialect of the non-Oracle system.
Translating queries that reference Oracle data dictionary tables to queries that extract the necessary information from the non-Oracle system's data dictionary.
Converting data from non-Oracle system data types to Oracle data types and back.
Compensating for missing functionality of the non-Oracle system by issuing multiple queries to get the necessary data and doing postprocessing to get the desired results.