Multiple Databases

Multiple databases can be loaded in a single AutoCAD session. Each object in the session has a handle and an object ID. A handle uniquely identifies the object within the scope of a particular database, whereas an object ID uniquely identifies the object across all databases loaded at one time. An object ID only persists during an edit session, but a handle gets saved with the drawing. In contrast to the object ID, an object handle is not guaranteed to be unique when multiple databases are loaded in an AutoCAD session.