Ora 12154 Tns Could Not Resolve the Connect Identifier Specified

Ora 12154 Tns Could Not Resolve The Connect Identifier Specified

The error “Ora 12154 tns could not resolve the connect identifier specified” message is the most typical Oracle error. This error notification explains the consumer tried to hook up with a database title that isn’t saved or thought of unknown to the system.Ora 12154 Tns Could Not Resolve The Connect Identifier Specified

In this text, the reader will perceive the causes behind this error and the way they’ll clear up it. Let’s get began!

Why Does the “Ora 12154 Tns Could Not Resolve the Connect Identifier Specified” Issue Occurs?

The “ora 12154 tns could not resolve the connect identifier specified” message happens when there is a matter whereas making a reference to one in every of the Oracle companies or database situations.

This error is known as “ORA-12154: TNS:could not resolve service name in some Oracle databases.” However, there are a number of explanation why this error message happens.

Sometimes, the join identifier shouldn’t be capable of resolve, which occurs because of the following causes:

  1. Trying to hook up with an unknown database.
  2. Typo or syntax error.
  3. Inability to hook up with the repository due to unplanned server and community outages.
  4. The entry is lacking from tnsnames.ora.
  5. The entry in tnsnames.ora is malformed.
  6. No default area is enabled in the sqlnet.ora.

– Trying To Connect to an Unknown Database

This error happens when a programmer tries to attach a file to an unknown database. This is as a result of the database that has been typed in doesn’t exist in the dictionary or saved in the program. Thus, it’s thought of unknown by the program.

A connection to a database and different companies is requested by utilizing a join identifier, and when the join identifier specified shouldn’t be resolved right into a join descriptor by utilizing one in every of the naming methodologys configured, the error happens.

– Typo or Syntax Error

One of the most typical causes behind Oracle errors is the typo or syntax errors a programmer makes whereas coding. The join identifier error happens when a typo happens in the connection string or community configuration information. Some widespread errors embrace:

  1. Ora-12154: tns:couldn’t resolve the join identifier specified 19c.
  2. Ora-12154: tns:couldn’t resolve the join identifier specified Linux.
  3. Impdp ora-12154: tns:couldn’t resolve the join identifier specified.
  4. Ora-12154: tns:couldn’t resolve the join identifier specified (dbd error: ociserverattach).

– Inability To Connect to the Repository Because of Unplanned Server and Network Outages

When the file can not hook up with the repository, it might be because of the unplanned server and community outages. This implies that the goal server may’ve been briefly gone down, which is why the subject is more likely to happen on all these PCs through which the programmer makes an attempt to entry the community.1674293920 208 Ora 12154 Tns Could Not Resolve The Connect Identifier Specified

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Sometimes, connection points may also be the wrongdoer behind this error. Additionally, the programmer could use a service or community whose vacation spot title doesn’t match the enter deal with.

For instance, suppose a sort of join identifier utilized by the programmer was a web service title, and it was not saved in the dictionary. In that case, the web service title couldn’t be present in the naming methodology repository, or the repository couldn’t be positioned and reached.

– The Entry Is Missing From Tnsnames.ora

Tnsnames are native naming information. A connection error message happens as a result of the programmer by accident misses mentioning the filename or a perform to entry tnsnames.ora.

When the filename shouldn’t be correctly known as, the code won’t be able to entry the service, and so the error will happen.

– The Entry in tnsnames.ora Is Malformed

Sometimes, the entry in the tnsnames.ora file is malformed, in all probability due to the spelling error, so it causes the connection error message to happen. Therefore, the programmer ought to make sure to verify their tnsnames.ora and listener.ora information.

Moreover, the error will happen if the ORACLE_HOME and ORACLE_SID will not be set to the correct surroundings. Sometimes, the programmer has to ensure that their TNS_ADMIN parameter is ready in the event that they’re utilizing an alternate location for these configuration information as a result of if it’s not set, the error will happen.

– No Default Domain Is Enabled in Sqlnet.ora

The error happens when no area is enabled in sqlnet.ora. The sqlnet.ora has a number of parameters, and if these parameters are coded flawed by the programmer, the error will happen. The default area is enabled in sqlnet.ora community to be able to set a site from which the consumer usually appears to be like up title decision requests.

For instance, when the “connect” string features a area extension, reminiscent of: join.john@gross sales.us.instance.com, the area is not going to be appended to the string. It could be written as: NAMES.DEFAULT_DOMAIN=instance.com. Let’s take an instance for higher understanding:

For instance:

In the following instance, the programmer tries connecting the oracle database with SQL Developer. They put in the .Net oracle drivers and positioned the tnsnames.ora file in

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The format the programmer utilized in tnsnames.ora is:

dev =




(SERVICE_NAME = idpdev2)



Therefore, when the programmer tries to create a brand new connection in SQL Developer, no TNS-names present up as choices, together with an error message.

How To Fix The Ora 12154 Tns Error?

The first step to resolve the “ora 12154 tns could not resolve the connect identifier specified” error is to know which title decision methodology is used at the programmer’s website. Commonly, there are a lot of websites that use tnsnames.ora, however a few of them use Oracle Names and LDAP additionally.

Therefore, it’s best to substantiate this data to keep away from error messages. Moreover, if the consumer shouldn’t be the database administrator, then they need to get in contact with the individuals managing their Oracle programs and discover out which methodology the consumer ought to use. They will be capable to information the consumer in fixing the drawback in accordance with their website’s requirements.

Furthermore, the consumer code decides which mechanism is finest to make use of based mostly on the file sqlnet.ora. The file and tnsnames can normally be present in the Oracle put in listing, additionally known as ORACLE_HOME, below community/admin/. However, this location could be overridden by the surroundings variable TNS_ADMIN, so watch out. If the sqlnet.ora file doesn’t exist or specify a decision methodology; Oracle Net makes use of tnsnames.ora.

There are varied strategies to repair this error. We have listed and defined them for higher understanding.

– Use a Flat File Named Tnsnames.ora

To eliminate this error, be certain that there are not any syntax errors in TNSNAMES.ORA. The programmer ought to search for unmatched parentheses or stray characters. If the error shouldn’t be corrected, the TNSNAMES.ORA file might be unusable. If the tnsnames.ora file isn’t getting acknowledged, use the following process:

  1. The programmer ought to outline an environmental variable known as TNS_ADMIN. Doing so will level to the folder that incorporates the tnsnames.ora file.
  2. In Windows OS, that is performed by opening the Control Panel, then deciding on System and Advanced system settings, after which clicking on surroundings Variables. Moreover, in Linux, the programmer ought to outline the TNS_ADMIN variable in the .profile file of their house listing.
  3. Confirm if the OS acknowledges this environmental variable. Then, from the Windows command line, go to echo %TNS_ADMIN%, and from Linux, go to echo $TNS_ADMIN.
  4. Now restart SQL Developer.
  5. Once restarted, open SQL Developer and right-click on Connections to pick New Connection.
  6. Proceed to pick TNS as the connection kind in the drop-down field. The entries from tnsnames.ora ought to now be displayed right here.
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– Avoid Syntax Error

Try to keep away from syntax and typo errors or if the error occurred, verify all the packages once more to seek out and proper the errors. By eliminating syntax errors, the programmer can resolve a number of points, reminiscent of:1674293922 602 Ora 12154 Tns Could Not Resolve The Connect Identifier Specified

  • ora-12154: tns:couldn’t resolve the join identifier laid out in ssis.
  • pwx 36075 oci error ora-12154: tns:couldn’t resolve the join identifier specified.
  • databaseerror: ora-12154: tns:may.
  • ora-12154 tns couldn’t resolve the join identifier specified stackoverflow.

– Use the Correct Dictionary Naming Process

Use the appropriate dictionary naming course of to be able to take away the error message. Note that the process defined beneath is for many who use dictionary naming. The process consists of some steps, reminiscent of:

  1. The programmer has to first confirm the existence of “LDAP”. This could be performed by discovering it in the checklist of values of the NAME DIRETORY_PATH parameter in the Oracle.web profile.
  2. Now confirm that the LDAP listing server is up. It must be accessible.
  3. Check whether or not the web service title or database title used as a join identifier is configured in the Python listing.
  4. Finally, the consumer ought to confirm that the default context is getting used accurately. This could be performed by specifying the certified web service or a full LDAP DN as a join identifier.


After studying this text, the reader will know the causes behind this error together with the other ways to resolve it. Here are the key takeaways from this text:

  • This Oracle error is a typical error message for database directors.
  • Ensure the programmer troubleshoots the program fastidiously as a result of there’s multiple purpose such an error can happen.
  • Windows, UNIX and LINUX are the places the place Oracle networking information are included.
  • Use the join naming process correctly to be able to take away the error message.

Hence, the reader can now simply troubleshoot their Oracle error and resolve it utilizing the pointers supplied on this article. Thank you for studying!


  • https://stackoverflow.com/questions/425029/oracle-tns-names-not-showing-when-adding-new-connection-to-sql-developer
  • https://www.xtivia.com/weblog/ora-12154-tnscould-not-resolve-connect-identifier-specified/#:~:textual content=ORApercent2D12154percent3Apercent20TNSpercent3Acouldpercent20notpercent20resolvepercent20thepercent20connectpercent20identifierpercent20specified,-bypercent20XTIVIApercent20percent7Cpercent20Jan&textual content=This%20ispercent20onepercent20ofpercent20the,stringpercent20orpercent20networkpercent20configurationpercent20files.

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