Definitions
AutoCAD Handle The unique identifier that all AutoCAD entities have that remains the same throughout the life of the drawing. Even if other entities are added or deleted and the drawing is saved, the Handle persists through the life of drawing. The handle is a 16-character Alphanumeric identifier.
Database Key The identifier that uniquely identifies data in a Database Table
Room Layer A layer (or layers) that define where area outlines can be found.
Text Layer A layer (or layers) that define where area identifiers (Room Name, etc.) can be found.