Following error was encountered while enabling the adapter polling notification:

[ART.116.3038] Adapter Runtime (Notification): Error in Notification Callback:enableCallback notification Training.dbEntry:insertNotification.
[ADA.1.114] The database objects for “Training.dbEntry:insertNotification” notification already exist. You can delete the objects and try enabling the notification again. To delete the existing database objects use the “pub.pollingNotificationUtils:dropDatabaseObjects” service.

when i run the service “pub.pollingNotificationUtils:dropDatabaseObjects” and provide the notification as input and then try to enable the polling notification, following error was generated:

[ART.116.3038] Adapter Runtime (Notification): Error in Notification Callback:enableCallback notification Balaji.dbEntry:insertNotification.
[ADA.1.316] Cannot execute the SQL statement "CREATE TRIGGER WMTnotifybhidb32 AFTER INSERT ON BALAJI.employeeDetails FOR EACH ROW BEGIN INSERT INTO WMBnotifybhidb32 (Name, EmpNo, Designation, JoinedOn, ReportingTo, PreviousEmployer, wm_rowid) VALUES (:new.Name, :new.EmpNo, :new.Designation, :new.JoinedOn, :new.ReportingTo, :new.PreviousEmployer, WMSnotifybhidb32.NEXTVAL); END;
". "
(42000/942) ORA-00942: table or view does not exist
"
ORA-00942: table or view does not exist

Check help on Oracle DB error: ORA-00942
You can also check what user privileges your WM user has in ORACLE DB. I think this resolved my similar problem in the past.