Oracle C++ Call Interface Programmer's Guide

Working with Objects in OCCI
Transient Objects
Creating Embedded Objects: Example
This code example demonstrates how an embedded object is created:
CREATE TABLE department
(deptno number,
deptname varchar2(30),
manager person_t);
Objects which are stored in the manager column of the department table are
embedded objects. They do not have object identifiers, and they cannot be
referenced. This means they cannot be pinned in an OCCI application, and they also
never need to be unpinned. They are always retrieved into the object cache by value.
A transient object is an instance of an object type. Its lifetime cannot exceed that of
the application. The application can also delete a transient object at any time.
The Object Type Translator (OTT) utility generates two operator new methods
for each C++ class, as demonstrated in this code example:
class Person : public PObject {
.
.
.
public:
dvoid *operator new(size_t size); // creates transient instance
dvoid *operator new(size_t size, Connection &conn, string table);
// creates persistent instance
}
The following code example demonstrates how a transient object can be created:
Person *p = new Person();
Transient objects cannot be converted to persistent objects. Their role is fixed at the
time they are instantiated.
See Also:
3-4 Oracle C++ Call Interface Programmer’s Guide
■ Oracle9i Database Concepts for more information about objects