ERROR: ORA-01041: internal error ‘Hostdef extension doesn't exist.
This error appears when attempting to Reverse Engineer an Oracle Database in erwin Data Modeler
ORA-01041: internal error. hostdef extension doesn't exist.', is an Oracle Error indicating that the connection string entered, can't be found in the TNSNames.ora located on the system. The following steps can help resolve the error.
1. Make sure the full Oracle Client is installed, not Oracle Express or Oracle Lite, etc. They do not have required 3rd Party Files. Also the bit level of the Oracle Client should match the bit level of Data Modeler (both 32 or both 64 bit).
2. Test the connection using SQL Plus to validate connectivity outside of erwin, using the same connect information. If this connection also fails, further investigation with a DB Administrator should be taken
3. Do multiple Oracle Homes exist? When a new version of the Oracle Client is installed, it does not overwrite or remove the older versions. Ensure the Path environment variable correctly references the proper client (client which contains the proper TNSNames.ora file). The Path variable can be found in Control Panel under System Environment Variables.
4. Search the hard drive and rename/ remove any additional TNSNames.ora files to ensure no other instances are causing a problem.
5. Update the 'sqlnet.ora' file and add the following:
SQLNET.AUTHENTICATION_SERVICES = (NONE)
6. In erwin Data Modeler, try using the full connection string (Service Name = value) from TNSNames.ora as the connection parameter in Data Modeler
Testing Connection with third party tool: https://support.erwin.com/hc/en-us/articles/115001740332-How-to-test-the-Oracle-TNS-connection-for-erwin-Data-Modeler-
Contact Support: https://support.erwin.com/hc/en-us