Data integration middleware provides services that allow applications and development tools to view different underlying data structures and
data sources as a single data source. This means that an application is not affected by physical implementation of data structure. The
illustration below explains why this is important:
Just as RPCs deal with process interoperability between remote programs, there are products, known as
SQL Gateways,that support data integration remotely.
SQL gateways are useful when dealing with applications that have a high number of temporarily connected users and that possess heterogeneous database sources. This is frequently true of B2C applications. Many application servers now possess a similar form of SQL gateway functionality.
The next lesson discusses distributed object middleware.