Error - Oracle: ORA-12154: TNS

I was getting this as well, the solution for me was in the Server field to enter <server name>:<port>/<service name>.  Then in the authentication window, select Database and enter the username and pasword.

In my case I was able to fix it just putting Server/DB

I was just putting DB in the server name part

Look like the connection info you specified can't be resolved

Please see the following taken from http://stackoverflow.com/questions/7957955/ora-12154-could-not-resolve-the-connect-identifier-specified

1. Is there a tnsnames.ora file
2. Is there an entry in the file for the service
3. Can the application find the tnsnames.ora?

Your problem may well be number 3 - does the application run as a different user than when you run the console?

Oracle looks for the tnsnames.ora file in the directory defined in the TNS_ADMIN environment variable - If you are running as different users, then maybe the TNS_ADMIN environment variable is not set, and therefore it cannot find the file?

Hope this helps,

Hello, 

I'd make sure the ora client is installed properly, the string is correct and finally tnsnames.ora is up to date. This video might helps as well:

https://www.youtube.com/watch?v=EpeJrO5tHDc

I am unable to connect to Oracle Database.  getting an error - Details: "Oracle: ORA-12154: TNS:could not resolve the connect identifier specified". 

I am able to connect to the same oracle database using Power Query in Excel but not able to connect with Power BI.  This tells me I have downloaded the correct Oracle Client with the correct TSN.ORA and Service names.

Can anybody help me find a solution. 

Thanks

Make sure your TNSNAMES.ORA file is updated to your new database in the oracle folder and it will work fine.  I had the same issue and couldn't figure out what was happening, turns out the DB Admins changed the database hostname.  Went in changed the tnsnames.ora file name to the new database connections and power BI connected with no problem.

=========linux useful=======

nmon

====================================================spool log==============

column tm new_value tm
column db new_value db
set feed on
set echo on
set time on
set timing on
set lines 1000 pages 1000
select to_char(sysdate, 'DD_MM_YYYY') tm from dual ;
select name db from v$database;
SPOOL OAS_&no._&tm._&db..log;

===========BLACKOUT==============

./emctl start blackout DR_DRIL_ACTIVITY -nodelevel -d 48:00
./emctl stop blackout DR_DRIL_ACTIVITY
./emctl status blackout

ps -ef|grep agent

cd /oracle/axoraadm/AGENT13C/agent_13.5.0.0.0/bin
./emctl status agent
./emctl start blackout bk_downtime -nodelevel -d 03:00
./emctl status blackout

========================grep command==============

grep -i "GENERAL_ACCT_MAST_TABLE" *

grep -i "GENERAL_ACCT_MAST_TABLE" * | grep -i 'stat'

cat table_stats.log | grep -i 'GATHER'

===============linux commands===========

===================stale tables===========

set line 200
select owner,table_name,stale_stats,last_analyzed from dba_tab_statistics where owner=upper('&owner') and stale_stats='YES' and TABLE_NAME not like '%TMP';

===================active session=========

set line 300 pages 400
set feedback on;
col SPID for a15
col USERNAME for a15
col LOGONDATE for a25
col OSUSER for a15
col SQL_ID for a18
col MODULE for a25
select a.sid,b.spid,a.username,
to_char(a.logon_time,'DD-MON-YYYY HH24:MI:SS') LogonDate,a.osuser,a.sql_id , a.status, a.module,a.last_call_et
from gv$session a, gv$process b where a.paddr = b.addr
and a.status = 'ACTIVE' and a.username is not null
order by 9 desc;

====================INDEX==========

SELECT name, height,lf_rows,lf_blks,del_lf_rows FROM INDEX_STATS;

select count(*) from INDEX_STATS where height ='2';

select index_name,status,owner from dba_indexes where status!='VALID';

select index_name,status,owner from dba_indexes where status!='VALID';

select count(*) from dba_indexes where owner='MX_FIN29' and status='VALID';

select OBJECT_NAME,OWNER,CREATED from dba_objects where OBJECT_TYPE='INDEX' and OWNER='MX_REP'order by created FETCH FIRST 50 ROWS ONLY ;

create index MX_REP.IDX_231660001 on MX_REP.AXE_TO_FX_01_MK_REP("M_V_EVT_CLS","M_TP_INT","M_REF_DATA");

select degree,count(1) from dba_indexes where owner='MLC' group by degree;

select degree,INDEX_NAME from dba_indexes where owner='MX_FIN' and DEGREE='0';


select degree,INDEX_NAME from dba_indexes where owner='MX_FIN' and DEGREE='0';


alter



SELECT
'alter index '||OWNER||'.'||INDEX_NAME||' noparallel;'
FROM
DBA_INDEXES
WHERE
degree <> 'DEFAULT'
AND to_number(DEGREE) not like '%1%' and INDEX_TYPE not like '%LOB%' and owner='MX_REP'
-- put any exclusions here
--AND INDEX_NAME NOT IN ('BINARY_SEARCH_INDEX','TEXT_SEARCH_INDEX','SIMPLE_SEARCH_INDEX')
ORDER BY
INDEX_NAME
/

SELECT
'alter index '||OWNER||'.'||INDEX_NAME||' noparallel;'
FROM
DBA_INDEXES
WHERE
degree not like '%1%'
ANDINDEX_TYPE not like '%LOB%' and owner='MX_REP'
-- put any exclusions here
--AND INDEX_NAME NOT IN ('BINARY_SEARCH_INDEX','TEXT_SEARCH_INDEX','SIMPLE_SEARCH_INDEX')
ORDER BY
INDEX_NAME
/

select 'alter index "'||owner||'"."'||index_name||'" noparallel;' from dba_indexes where DEGREE like '%20%';