Problem: You are trying to access oracle database using sqlplus, or using forms builder, or using oracle reports builder and Toad.
ERROR: ORA-12560: TNS:protocol adapter error: No listener.
Solution: check the status of the Database listener by Running the Command Prompt with this code : lsnrctl status
if the command completed unsuccessfully start the Listener by running the Command Prompt with this code : lsnrctl start
if the above does not work.
go to C:\oraclexe\app\oracle\product\10.2.0\server\NETWORK\ADMIN on your local machine
check if the host name of the listener and tnsnames are the same as to your pc name.
Eg: Tns LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
(ADDRESS = (PROTOCOL = TCP)(HOST = Example_PC or IP_ADDRESS)(PORT = 1521))
)
)
DEFAULT_SERVICE_LISTENER = (XE)
Eg: Tnsnames XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = Example_PC or IP_ADDRESS)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
)
)