By default, any user who can create or manage an application can create a data set from a data source in the Data Source Library. You can, however, restrict access to the data source to only allow certain roles, users, or user groups to use the data source.

Note that this only controls whether a user can create an application from the data source. It does not control access to the specific data. For Oracle BI data sources, access to the data is controlled using the permissions in the RPD file.
To configure access to a data source: