The figure shows representations of the `PurchaseOrder_objtab` and `Customer_objtab` object tables. A line representing a reference connects the attribute `Cust_ref` of the `Customer_objtab` table to the `PurchaseOrder_objtab` table.

The figure is a graphical representation of the `CREATE` `TABLE` `PurchaseOrder_objtab` statement and the description of the `PurchaseOrder_objtyp` type that precede the figure in the text. The figure is also a graphical representation of the `CREATE` `TABLE` `Customer_objtab` statement (also shown in Figure A-3).