ORA-03114: Not Connected to Oracle

I got ” ORA-03114: Not Connected to Oracle ” error in Oracle database.

ORA-03114: Not Connected to Oracle

Details of error are as follows.

ORA-03114 not connected to ORACLE

Cause: A call to Oracle was attempted when no connection was established. 
Usually this happens because a user-written program has not logged on. It may also happen 
if communication trouble causes a disconnection.

Action: Try again. If the message recurs and the program is user written, check the program.

Not Connected to Oracle

This ORA-03114 errors are related with the call to Oracle was attempted when no connection was established.
Usually this happens because a user-written program has not logged on. It may also happen if communication trouble causes a disconnection.

Usually this error is get when database Connection issue exists, so check database connection again.

Check your Network or Firewall issues, application server is disconnected from database server because of network issues.

Check listener of database if it is running or not.

Check tnsnames.ora if the database connection string is correct or not.

Do you want to learn Oracle Database for Beginners, then read the following articles.

Oracle Tutorial | Oracle Database Tutorials for Beginners ( Junior Oracle DBA )