ORA-12154 TNS could not resolve the connect identifier specified PLSQL Developer

Question

I need to use PLSQL Developer to access oracle databases  I get the following error when I try to connect to my database  ORA-12154  TNS could not resolve the connect identifier specified  I am able to use SQLPLUS from the command line to connect to the database  and tnsping returns successfully  but I can t figure out why PLSQL Developer will not work - it s using the right tnsnames ora file  and the connection string in there is correct because it s the same one that tnsping uses   Anyone have an idea what I can do to fix this  I ve looked at other threads about this specific error with no luck   tnsnames ora      ORCL          DESCRIPTION           ADDRESS    PROTOCOL   TCP  HOST   MININT-AIVKVBM  PORT   1521           CONNECT DATA             SERVER   DEDICATED            SERVICE NAME   orcl                  sqlnet ora       SQLNET AUTHENTICATION SERVICES   NTS       NAMES DIRECTORY PATH   TNSNAMES  EZCONNECT    sqlpus command line image here  PLSQL Developer Connection Preferences  image here

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Just wanted to add -- apparently this can also be caused by installing Instant Client for 10  then realizing you want the full install and installing it again in a parallel directory   I don t know why this broke it

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copy paste pl sql developer in program files x86 and program files both  if client is installed in other partition drive then copy pl sql developer to that drive also  and run from pl sql developer folder instead of desktop shortcut    ultimate solution   chill

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I had the same issue with a VM running CentOS7 and Oracle 11GR2 accesible from Windows 7  the solution were weird  at my local machine the tnsnames pointing to the DB had a space before the service name  I just deleted the space and then I was able to connect   A quick example   Wrong tnsnames    this is a empty space XE      DESCRIPTION        ADDRESS    PROTOCOL   TCP  HOST   127 0 0 1  PORT   1521        CONNECT DATA          SERVER   DEDICATED         SERVICE NAME   XE             EXTPROC CONNECTION DATA      DESCRIPTION        ADDRESS LIST          ADDRESS    PROTOCOL   IPC  KEY   EXTPROC FOR XE              CONNECT DATA          SID   PLSExtProc         PRESENTATION   RO             Right tnsnames   XE      DESCRIPTION        ADDRESS    PROTOCOL   TCP  HOST   127 0 0 1  PORT   1521        CONNECT DATA          SERVER   DEDICATED         SERVICE NAME   XE             EXTPROC CONNECTION DATA      DESCRIPTION        ADDRESS LIST          ADDRESS    PROTOCOL   IPC  KEY   EXTPROC FOR XE              CONNECT DATA          SID   PLSExtProc         PRESENTATION   RO

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As I can t add a comment  just thought I d post this for completion  tufy s answer is correct  it s to do with parenthesis  brackets  in the path to the application being run      There is an existing networking bug where the networking layer is   unable to parse program locations that contain parenthesis in the path   to the executable which is attempting to connect to Oracle    Filed with Oracle  Bug 3807408 refers   Source

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Also in addition to above solutions  also check the location where the tnsname ora file exists and compare with the path in the environment variable

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This error is very common  often the very first one you get on trying to establish a connection to your database   I suggest those 6 steps to fix ORA-12154     Check instance name has been entered correctly in tnsnames ora   There should be no control characters at the end of the instance or database name  All paranthesis around the TNS entry should be properly terminated Domain name entry in sqlnet ora should not be conflicting with full database name  If problem still persists  try to re-create TNS entry in tnsnames ora  At last you may add new entries using the SQL Net Easy configuration utility    For more informations   http   turfybot free fr oracle 11g errors ORA-12154 html

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I had an issue at work  The oracle server was  patched  and one of the databases I use could not be connect via the TNSNames entry but via Basic connection  The Database was up and admin could see it was up and running   Addionally any application that used TNS for connecting to the database would not work either   The problem found was that the database name was not correct in the TNS file but for some reason it s been working for years  Correcting the name fixed it for us  I did find that Oracle SQL Developer kept using the old TNS entry even after I updated it and I don t feel like reinstalling it for just one DB Connection  It appears that when the database was created it was given a smaller name then the others and via some cut and paste action within the TNSNames file it got mixed up  No one is sure how its worked as we re investigating it but the oracle patch ensured that the name had to be correct  An example of the name was it was down as  DBName Part1 Part2  but in fact the DB name was  DBName

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The answer was simply moving the PLSQL Developer folder from the  Program Files  x86  into the  Program Files  folder - weird

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ORA-12154  TNS could not resolve the connect identifier specified  PLSQL Developer   Answer  Go to the folder where you have installed ORACLE DATABASE  such as E  oracle product 10 2 0  or as your oracle version  db-1 network ADMIN and then copy the two files  1  sqlnet ora   2  tnsnames ora and close this folder  Go to the folder where you have installed ORACLE DEVELOPER  such as E  DevSuitHome 1 NETWORK ADMIN then rename the two files  1  sqlnet ora   2  tnsnames ora and paste the two copied files here and Your are OK

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JUST copy and paste tnsnames and sqlnet files from Oracle home in PLSQL Developer Main folder  Use below Query to get oracle home  select substr file spec  1  instr file spec       -1  2  -1  ORACLE HOME     from dba libraries     where library name    DBMS SUMADV LIB

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For me it was bad formatting of the tnsnames ora connect identifier  The indentation of the identifier string is required as shown in the tnsnames ora example in the comment

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It did not work so i switched to oracle sql developer and it worked with no problems  making connection under 1 minute   This link gave me an idea connect to MS Access so i created a user in oracle sql developer and the tried to connect to it in Toad and it worked   Or second solution you can try to connect using Direct not TNS by providing host and port in the connect screen of Toad

[oracle] ORA-12154: TNS:could not resolve the connect identifier specified (PLSQL Developer)

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