Sql developer could run and connect to db right After installation 12c in Redhat yesterday.
Today It won't run. Lsnrctl status tells "the listener supports no services".
Tnsping to the service name "oraedu" or the IP address of redhat responds OK.
Some advise "alter system register". But I can't comprehand their advice and can't find how to start sql plus.
I need some help...
how to run sql plus in redhat.
how to solve listener problem.
My host pc : window 7
Guest pc : redhat in vmware
oracle dbms : 12c