For example, a purchase order can be represented as an object. Attributes can
include a purchase order number, a vendor, a vendor address, a ship-to address, and
a collection of items (with their associated quantity and price). You can use a method
to add an item to the purchase order, delete an item from the purchase order, or
return the total amount of the purchase order.
You can store objects as rows in tables or as values in columns. Each row object has
a unique object identifier (OID) created by Oracle. Row objects can be referred to
from other objects or relational tables. The REF datatype represents such references.
For column objects, Oracle adds hidden columns for the object??™s attributes.
Object views provide a means of creating virtual object tables from data stored in the
columns of relational tables in the database. These views can also include attributes
from other objects. Object views are created by defining an object type, writing a
query defining the mapping between data and tables containing attributes for that
type, and specifying a unique object identifier.
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