freeze
freeze() updating;
The freeze method of the class converts a database partition to read-only mode after which all object update, delete, or create operations are not permitted. (See also the thaw method.)
All objects in a frozen partition are automatically frozen, overriding individual volatility state.
An exception is raised if the database partition was not located, there was an error accessing a database partition control file, an attempt was made to access an offline partition, the partition is locked for administrative purposes, the partition is required for object creation, the database is locked for reorganization, or you are attempting the freeze operation when the database is in backup state.