Oracle C++ Call Interface Programmer's Guide

Developing an OCCI Object Application
Pin Object
In most situations, OCCI users do not need to explicitly pin or unpin the objects
because the object cache automatically keeps track of the pin counts of all the
objects in the cache. As explained earlier, the object cache increments the pin count
when a reference points to the object and decrements it when the reference goes out
of scope or no longer points to the object.
But there is one exception. If an OCCI application uses Ref::ptr() method to
get a pointer to the object, then the pin and unpin methods of the PObject class
can be used by the application to control pinning and unpinning of the objects in
the object cache.
Operate on Object in Cache
Note that the object cache does not manage the contents of object copies; it does not
automatically refresh object copies. Your application must ensure the validity and
consistency of object copies.
Flush Changes to Object
Whenever changes are made to object copies in the object cache, your application is
responsible for flushing the changed object to the database.
Memory for the object cache is allocated on demand when objects are loaded into
the object cache.
The client-side object cache is allocated in the program's process space. This object
cache is the memory for objects that have been retrieved from the database server
and are available to your application.
Note: If you initialize the OCCI environment in object mode, your
application allocates memory for the object cache, whether or not
the application actually uses object calls.
There is only one object cache allocated for each OCCI environment. All objects
retrieved or created through different connections within the environment use the
same physical object cache. Each connection has its own logical object cache.
Deletion of an Object
For objects retrieved into the cache by dereferencing a reference, you should not
perform an explicit delete. For such objects, the pin count is incremented when a
Object Programming 3-11