An object has a persistent reference to a missing object.
If an object is stored and it has a reference to another object that does not exist (for example, it was deleted by pack), this exception may be raised. Whether a storage supports this feature, it a quality of implementation issue.
Instance attributes: referer: oid of the object being written missing: referenced oid that does not have a corresponding object
There are no attributes in this class.
There are no methods in this class.
There are no known subclasses.