Error::ORA-12154: TNS:could not resolve service name

If error comes as follows:
　


ORA-12154: TNS:could not resolve service name
　



STEPS TO SOLVE IT ARE:-

　

1.Check the entries in the TNSNAMES.ORA file located at

({ORACLE_HOME/DBS/TNSNAMES.ORA}) is proper.

　

2.Check it is according to the SQLNET.ORA file located at

({ORACLE_HOME/DBS/SQLNET.ORA})

　

#NAMES.DEFAULT_DOMAIN = VALUE

　

Note: here NAMES stand for instance_name in TNSNAMES.ORA


IF
NAMES.DEFAULT_DOMAIN = VALUE (IS UNCOMMENTED)

(like NAMES.DEFAULT_DOMAIN = VALUE)


THEN
instance_name look like NAMES.VALUE in TNSNAMES.ORA


IF
NAMES.DEFAULT_DOMAIN = VALUE (IS COMMENTED)

(like #NAMES.DEFAULT_DOMAIN = VALUE)


THEN
instance_name look like NAMES in TNSNAMES.ORA

　

EXAMPLE


1.SQLNET.ORA file entries


　
# SQLNET.ORA Network Configuration File: /u01/app/oracle/product/9.2.0/network/admin/sqlnet.ora

# Generated by Oracle configuration tools.

　

#NAMES.DEFAULT_DOMAIN = test.in

　

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)

　

Note:( here test.in is DEFAULT_DOMAIN) WHICH IS COMMENTED HERE .

　

　

TNSNAMES.ORA file entries


testdb=

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = db.test.in)(PORT = 1521))

)

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = test)

)

)

　

Note: because of

#NAMES.DEFAULT_DOMAIN = test.in

is commented thats why in TNSNAMES.ORA INSTANCE_NAME IS test

　



2 SQLNET.ORA file entries

　

# SQLNET.ORA Network Configuration File: /u01/app/oracle/product/9.2.0/network/admin/sqlnet.ora

# Generated by Oracle configuration tools.

　

NAMES.DEFAULT_DOMAIN = test.in

　

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)

　

Note:( here test.in is DEFAULT_DOMAIN) WHICH IS UNCOMMENTED HERE .




TNSNAMES.ORA file entries

　

testdb.test.in=

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = db.test.in)(PORT = 1521))

)

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = test)

)

)

　

Note: because of

#NAMES.DEFAULT_DOMAIN = test.in

is uncommented thats why in TNSNAMES.ORA INSTANCE_NAME IS test.test.in.