The Oracle Open Gateways (previously called SQL*Connect) is a product that can be used to access data from non-Oracle databases (eg. DB2, Sybase, Informix, etc), and even non-relational data sources like Adabas and file systems.
Oracle Open Gateways can be divided into 4 categories: Transparent Gateways, Procedural Gateways, Access Managers and Oracle Replication Servers:
 Transparent Gateways
Transparent Gateways are most commonly used and enable access to non-Oracle data sources as if they were Oracle databases. They allow you to interact with these foreign databases without regard to differences in SQL implementation and with the added ability to perform distributed processing.
Some of the available transparent gateways:
 Procedural Gateways
Procedural Gateways are used to integrate with non-relational data sources. Normally a toolkit is used to map foreign database functions to PL/SQL stored procedures. These PL/SQL procedures can be called from any Oracle product like Oracle Forms and SQL*Plus.
Some of the available procedural gateways:
- Procedural Gateway for APPC (Advanced Program to Program Communications)
- Procedural Gateway for MQSeries
 Access Managers
Some of the available access managers:
- IBM CICS
- IBM IMS/TM
- IBM AS/400
 Replication Servers
Replication Servers support heterogeneous data replication (Oracle to on-Oracle).
Some of the available replication servers:
- Oracle Replication Server for IBM's DataPropagator
 Also see
- Generic connectivity - Free, but slower ODBC connectivity to other database systems