\subsubsection{Locked values}
The data contained in the \ucsName{temporary} container are created
and used on a program-internal basis exclusively.

The values of some of the attributes have to be unique. If a certain
value is to be set, a search within the LDAP directory will be
performed beforehand in order to check whether the value is already in
use.

Values presently edited - and therefore not accessible for search -
are locked during editing in order to ensure that these values are not
used a second time. Such values are reserved for the editing process
and cannot be utilised by any other process. Once editing is finished,
the lock is lifted.

In case of an error, a lock can sometimes persist by accident. To
ensure an error-free operation, \ucsUDM{} automatically releases
locked values after a maximum locking time (five minutes).

Locked  values are stored in the appropriate containers beneath the
\ucsName{temporary} container, and are checked and, eventually, deleted in
\ucsUDM{} like any other objects. Manual deleting is not recommended
except in special cases:

\begin{itemize}
\item If, due to an error, the lock was not lifted, and the value is to be
used again before the locking time is expired. In such a case, it has
to be ensured that the persistence of the lock is indeed due to an
error, and not just to the fact that another process has made access
to the value in the meantime.

\item The lock was lifted, yet the locked object was not automatically
removed from
\ucsName{cn=<subcontainer>,cn=temporary,cn=univention,<Base-DN>}. Such
objects do not disturb the program flow, they will be overwritten by
\ucsUDM{} as soon as the necessity arises.
\end{itemize}

\begin{ucsTabbox}{'General' tab}
\ucsTabentry{Name (*)}
The name of the locked object. The name corresponds to the value to be
set as the attribute.

\ucsTabentry{Locked until}
The time (in seconds), from 1 January 1970 onwards, when the object is
automatically released after the expiry of the maximum locking time.
\end{ucsTabbox}

