Relational Data Source Support
Relational data source support is provided as follows:
• The gateway acts as an intermediary by performing the following functions:
– Translating OpenSQL queries to native DBMS dialect
– Translating the Enterprise Access scalar functions into the equivalent native DBMS functions or SQL expressions using SQL Scalar Function translation maps
– Transforming OpenSQL data types to native DBMS data types
– Handling OpenSQL meta data queries
– Physically interfacing to native data sources
– Handling responses and results from native DBMS
• Assumptions underlying relational data source support include the following:
– The underlying DBMS can handle at least SQL89 queries.
– The host DBMS handles aggregate processing.
– The DBMS handles query optimization and processing.
– DBMS catalogs are normalized and can be accessed through relational queries.