ORA-12154 error, TNS: Could Not Resolve the Connect Identifier Specified
hostName, port number, and service name
tnsnames.ora
$ORACLE_HOME/network/admin
service name, host, port, and other connection
Oracle Net service
TNS Listener
lsnrctl start LISTENER_NAME
tnsping service_name
service_name
ORACLE_HOME and TNS_ADMIN
ORACLE_HOME
TNS_ADMIN