Host String Problem

Question

Hi everyone, i searched the forum and found same problem with me but i did not work for me. The problem is i cannot connect my sql plus. i enter my username and password then it asks me gor host string but when i type it and enter "ok" it says "TNS Listener does not currentl know of service requested in connect descriptor. i looked at my tnsnames.ora file and is exactly like this.
# tnsnames.ora Network Configuration File: C:\oracle\product\10.2.0\db_1\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
CSE348 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = Canavar)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = cse348)
So what shoul i type to connect sql plus?

Answer 1

Given the tnsnames.ora content, the following needs to be entered for sqlplus in order to have it use that connection string in the file:
sqlplus scott/tiger@CSE348As you have not qualified the alias with a domain, it will default to "+.world+" as far as I recall. If the default domain in your local sqlnet.ora differs, than that default will be used to find alias CSE348 in the local tnanmes.ora file. So make sure that you do not mix default and explicit domain names. Rather specify a default domain in sqlnet.ora and use the same domain for defining full qualified domain name TNS aliases in tnsnames.ora.
As for the error - the Listener receives a connection request for a service called cse348 - and no such service has registered with it. You can check the known services of the listener using the "+lsnrctl services+" command on the server.
Often in this case, it is easier to request a specific database instance using its system identifier, or SID. In which case you can change your connection string for the alias to use a SID as follows:
CSE348 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = Canavar)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SID = cse348)
  )This assumes that the SID is cse348. The default SID is for example orcl. SIDs like dev and prod are also often used.