The Database/Call Procedure template (and plugin) is provided for that purpose exactly.
It includes support for IN and OUT parameters, as well as result sets. INOUT parameters are not supported, but I'm sure you could workaround that limitation.
The plugin has been implemented using JDBC, and has been widely used in our projects based on SQL Server and DB/2, but it should work equally well with all supported databases.
As with all database functionality, commercial databases (such as Oracle) are supported by our enterprise version.
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