Oracle Database connection issues

ORA-12514: TNS:listener does not currently know of service

ORA-12541: TNS:no listener

ORA-12545: Connect failed because target host or object does not exist

ORA-12154: TNS:could not resolve the connect identifier specified

ORA-12560: TNS:protocol adapter error

ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

 

Ed Stevens has an excellent post for all sorts of Oracle connection problems

http://edstevensdba.wordpress.com/2011/03/19/ora-12514/

http://edstevensdba.wordpress.com/2011/02/09/sqlnet_overview/