Object model to ER diagrams

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Object model to ER diagrams

**Figure 8:** Class Heirarchies - Object model
$\begin{figure} \centerline{ \psfig {figure=object.eps} }\end{figure}$

The various objects in the object model are represented as entities in the ER diagram and the association between the objects is represented as a relationship. For e.g. the Location object in the object model is represented by the Location entity in the ER diagram. The attributes of the Location entity are shown within the ovals in the figure. Also the building and Parking lot objects are mapped to Building and Parking lot entities with corresponding attributes. The relationship between the Location entity and the Building entity is defined as an ISA(``is a'') relationship which implies that each Building is a Location. Same is true with Parking lot.

**Figure 9:** Class Hierarchies - ER model
$\begin{figure} \centerline{ \psfig {figure=final.eps} }\end{figure}$

Scott P Kaminski
4/17/1998