SDB_Extension - Property extension

A property extension is an internal data type, that manages property extensions for database instances. Property extensions are stored by an internal property number assigned to the property definition. The property value is referred to by the database entry number (collection LOID), when the extension property is a reference or relationship. When the extension property is an attribute, the attribute value is stored directly. Thus, attribute values must not exceed the entry number size of 8 bytes.