OutSystems integrates natively with several of the major database systems: SQL Server, SQL Azure, Oracle, MySQL, and DB2 iSeries.
It also has a database integration SDK, so that organizations can integrate with a database of choice. Developers can combine local and external data sources without spending much time on complex integration projects.
Query and aggregate data, visually
The OutSystems visual editor allows development teams to query and aggregate data visually so developers with any skill set can work with the complex data needed for any application.
OutSystems doesn't limit developers to manipulating data visually. They can write queries and stored procedures using standard SQL.
When doing so, OutSystems tracks all the dependencies to the underlying database. If it changes, your SQL code is automatically refactored, or you're warned if it is no longer compatible with the changes.
This accelerates the change process, and makes your application much more resilient to change.
Integrate with external databases
If an external database is natively supported by OutSystems, a developer can create a connector to integrate with it. Connectors enable teams to manipulate data visually in the visual editor.
When a database is not natively supported, it's still possible to access it using standard code, with ODBC/JDBC drivers, or native APIs. For big data repositories, like CouchDB, MongoDB, or Hadoop, developers access them using their REST APIs.
There is also an OutSystems database integration SDK for extending the platform, and it can be used to add native support for databases. However, any developer considering developing a custom connector should browse OutSystems Forge, which also has connectors, before starting. Most likely someone has already built and shared the connector you need.