I create a subreport with some data from a database table with a JDBC-Connection. The data can be changed with a parameter (p_sub). Now I want use this subreport in a mainreport. The mainreport also has a parameter (p_main). I join the parameter (p_sub) from the subreport with the parameter (p_main) from the mainreport. But if there is no connection in the mainreport I do not see the data of the subreport.
How can I perform a subreport with it's own connection and without any datasource connection in the mainreport?