Connection setup from MSSQL through Oracle 11.2g

Question

Hi folks,
I would like to query some data from MS SQL database through Oracle. In other forum I was pointed to Heterogenous Services, but unfortunatelly I'm having a problem with an initial set up.
Documentation I check:
http://docs.oracle.com/cd/E11882_01/server.112/e11050/admin.htm
http://docs.oracle.com/cd/B19306_01/server.102/b14232/admin.htm
Here is my scenario:
On the same server we are running Oracle database (11g release 11.2) and MS SQL (Microsoft SQL Server Express Edition (64-bit)).
Oracle database:
tnsnames.ora
# tnsnames.ora Network Configuration File: C:\Oracle\product\11.2.0\dbhome_dev\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.
DEV =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = SERVER.AGT.local)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = DEV)
HELIOS =
   (DESCRIPTION=
       (ADDRESS = (PROTOCOL = TCP)(HOST = SERVER.AGT.local)(PORT = 1521))
       (CONNECT_DATA =
           (SERVICE_NAME = HELIOSDB)
       (HS = OK)
listener.ora
# listener.ora Network Configuration File: C:\Oracle\product\11.2.0\dbhome_dev\network\admin\listener.ora
# Generated by Oracle configuration tools.
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = SERVER.AGT.local)(PORT = 1521))
ADR_BASE_LISTENER = C:\Oracle
SID_LIST_LISTENER=
  (SID_LIST=
      (SID_DESC=
         (SID_NAME=HELIOSDB)
         (ORACLE_HOME=C:\Oracle\product\11.2.0\dbhome_dev)
         (PROGRAM=dg4odbc)
  )I'm not sure whether a listener part is configured correctly.
Also, what next should be done?
Where is defined a connection to MS SQL database?
Please guide me with this initial configuration if possible.
Kind regards,
Tomas

Answer 1

One more thing, as I made some modifications and maybe I skrewed it up :(
I've added 2 more SQL databases, so I modified my files as follows:
# tnsnames.ora Network Configuration File: C:\Oracle\product\11.2.0\dbhome_dev\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.
DEV =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = SERVER.AGT.local)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = DEV)
HELIOS =
   (DESCRIPTION=
       (ADDRESS = (PROTOCOL = TCP)(HOST = SERVER.AGT.local)(PORT = 1521))
       (CONNECT_DATA =
           (SERVICE_NAME = HELIOSDB)
       (HS = OK)
HELIOSSRO =
   (DESCRIPTION=
       (ADDRESS = (PROTOCOL = TCP)(HOST = SERVER.AGT.local)(PORT = 1521))
       (CONNECT_DATA =
           (SERVICE_NAME = HELIOSSRO)
       (HS = OK)
HELIOSFO =
   (DESCRIPTION=
       (ADDRESS = (PROTOCOL = TCP)(HOST = SERVER.AGT.local)(PORT = 1521))
       (CONNECT_DATA =
           (SERVICE_NAME = HELIOSFO)
       (HS = OK)
    )            listener
# listener.ora Network Configuration File: C:\Oracle\product\11.2.0\dbhome_dev\network\admin\listener.ora
# Generated by Oracle configuration tools.
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = SERVER.AGT.local)(PORT = 1521))
ADR_BASE_LISTENER = C:\Oracle
SID_LIST_LISTENER=
  (SID_LIST=
      (SID_DESC=
         (SID_NAME=HELIOSDB)
         (ORACLE_HOME=C:\Oracle\product\11.2.0\dbhome_dev)
         (PROGRAM=dg4odbc)
SID_LIST_LISTENER=
  (SID_LIST=
      (SID_DESC=
         (SID_NAME=HELIOSSRO)
         (ORACLE_HOME=C:\Oracle\product\11.2.0\dbhome_dev)
         (PROGRAM=dg4odbc)
SID_LIST_LISTENER=
  (SID_LIST=
      (SID_DESC=
         (SID_NAME=HELIOSFO)
         (ORACLE_HOME=C:\Oracle\product\11.2.0\dbhome_dev)
         (PROGRAM=dg4odbc)
  )  created 2 init files initHELIOSSRO.ora and initHELIOSFO.ora
Configured ODBC for each database, like in previous example
Created 2 db links:
CREATE PUBLIC DATABASE LINK heliossro CONNECT TO "usersro" IDENTIFIED BY "sropwd" USING 'HELIOSSRO';
CREATE PUBLIC DATABASE LINK heliosfo CONNECT TO "userfo" IDENTIFIED BY "fopwd" USING 'HELIOSFO';but when I run query ORA-28545 occures
SQL> select * from dual@HELIOSDB;
select * from dual@HELIOSDB
ERROR at line 1:
ORA-28545: error diagnosed by Net8 when connecting to an agent
Unable to retrieve text of NETWORK/NCR message 65535
ORA-02063: preceding 2 lines from HELIOSDB
SQL> select * from dual@HELIOSSRO;
select * from dual@HELIOSSRO
ERROR at line 1:
ORA-28545: error diagnosed by Net8 when connecting to an agent
Unable to retrieve text of NETWORK/NCR message 65535
ORA-02063: preceding 2 lines from HELIOSSRO