ORA-00000 normal, successful completion

Cause: An operation has completed normally, having met no exceptions.

Action: No action required.


ORA-00001 unique constraint (string.string) violated

Cause: An UPDATE or INSERT statement attempted to insert a duplicate key.

Action: Either remove the unique restriction or do not insert the key.


ORA-00017 session requested to set trace event

Cause: The current session was requested to set a trace event by another session.

Action: This is used internally; no action is required.


ORA-00018 maximum number of sessions exceeded

Cause: All session state objects are in use.

Action: Increase the value of the SESSIONS initialization parameter.


ORA-00019 maximum number of session licenses exceeded

Cause: All licenses are in use.

Action: Increase the value of the LICENSE MAX SESSIONS initialization parameter.


ORA-00020 maximum number of processes (string) exceeded

Cause: All process state objects are in use.

Action: Increase the value of the PROCESSES initialization parameter.


ORA-00021 session attached to some other process; cannot switch session

Cause: The user session is currently used by others.

Action: Do not switch to a session attached to some other process.


ORA-00022 invalid session ID; access denied

Cause: Either the session specified does not exist or the caller does not have the privilege to access it.

Action: Specify a valid session ID that you have privilege to access, that is either you own it or you have the CHANGE_USER privilege.


ORA-00023 session references process private memory; cannot detach session

Cause: An attempt was made to detach the current session when it contains references to process private memory.

Action: A session may contain references to process memory (PGA) if it has an open network connection, a very large context area, or operating system privileges. To allow the detach, it may be necessary to close the session's database links and/or cursors. Detaching a session with operating system privileges is always disallowed.


ORA-00024 logins from more than one process not allowed in single-process mode

Cause: An attempt was made to log in more than once from different processes for Oracle started in single-process mode.

Action: Log off from the other process.


ORA-00025 failed to allocate string

Cause: An application failed because Oracle ran out of memory.

Action: Restart Oracle with a larger SGA heap.


ORA-00026 missing or invalid session ID

Cause: The session ID string specified in the ALTER SYSTEM KILL SESSION command was invalid, or no string was specified.

Action: Retry the command with a valid session ID.


ORA-00027 cannot kill current session

Cause: An attempt was made to use ALTER SYSTEM KILL SESSION to kill the current session.

Action: If it is necessary to kill the current session, do so from another session.


ORA-00028 your session has been killed

Cause: A privileged user killed the session and it is no longer logged in to the database.

Action: Contact the database administrator. The administrator may be attempting to perform an operation that requires users to be logged out. When the database administrator announces that the database is available, log in and resume work.


ORA-00029 session is not a user session

Cause: The session ID specified in an ALTER SYSTEM KILL SESSION command was not a user session. For example, the session may be recursively started.

Action: Retry the command with a valid session ID.


ORA-00030 User session ID does not exist.

Cause: The user session ID no longer exists, probably because the session was logged out.

Action: Use a valid session ID.


ORA-00031 session marked for kill

Cause: The session specified in an ALTER SYSTEM KILL SESSION command cannot be killed immediately because the session is involved in a non-interruptible operation (for example, rolling back a transaction or being blocked by a network operation). The session has been marked to be killed as soon as possible after the current operation is done.

Action: No action is required for the session to be killed, but further executions of the ALTER SYSTEM KILL SESSION command on this session may cause the session to be killed sooner.


ORA-00032 invalid session migration password

Cause: The session migration password specified in a session creation call was invalid (probably too long).

Action: Retry with a valid password (less than 30 characters).


ORA-00033 current session has empty migration password

Cause: An attempt was made to detach or clone the current session and it has an empty migration password. This is not allowed.

Action: Create the session with a non-empty migration password.


ORA-00034 cannot string in current PL/SQL session

Cause: An attempt was made to issue a commit or rollback from a PL/SQL object (procedure, function, package) in a session that has this disabled by a ALTER SESSION DISABLE COMMIT IN PROCEDURE statement.

Action: Enable commits from PL/SQL in this session, or do not attempt to use commit or rollback in PL/SQL when they are disabled in the current session.


ORA-00035 LICENSE_MAX_USERS cannot be less than current number of users

Cause: Specified values for LICENSE_MAX_USERS is less than the current number of users.

Action: Check the license limit and drop extra users or purchase more licenses.


ORA-00036 maximum number of recursive SQL levels (string) exceeded

Cause: An attempt was made to go more than the specified number of recursive SQL levels.

Action: Remove the recursive SQL, possibly a recursive trigger.


ORA-00037 cannot switch to a session belonging to a different server group

Cause: An attempt was made to switch to a session in a different server group. This is not allowed.

Action: Make sure the server switches to a session that belongs to its server group.


ORA-00038 Cannot create session: server group belongs to another user

Cause: An attempt was made to create a non-migratable session in a server group that is owned by a different user.

Action: A server group is owned by the first user who logs into a server in the server group in non-migratable mode. All subsequent non-migratable mode logins must be made by the user who owns the server group. To have a different user log in non-migratable mode, the ownership of the server group will have to be changed. This can be done by logging off all current sessions and detaching from all existing servers in the server group and then having the new user login to become the new owner.


ORA-00050 operating system error occurred while obtaining an enqueue

Cause: Could not obtain the operating system resources necessary to cover an Oracle enqueue. This is normally the result of an operating system user quota that is too low.

Action: Look up the operating system error in your system documentation and perform the needed action.