Oracle C++ Call Interface Programmer's Guide

LOB Classes and Methods
Reading and Writing LOBs
A LOB opened when there is no transaction must be closed before the end of
session. If there are LOBs open at the end of session, then the openness is
discarded and no triggers of extensible indexes are fired.
OCCI provides methods for reading and writing LOBS. For nonstreamed reads and
writes, the following methods are used:
■ Bfile::read()
■ Blob::read() and Blob::write()
■ Clob::read() and Clob::write()
For streamed reads and writes, the following methods are used:
■ Bfile::getStream()
■ Blob::getChunkSize(), Blob::getStream(), and
Blob::writeChunk()
■ Clob::getChunkSize(), Clob::getStream(), and
Clob::writeChunk()
The remainder of this section provides code examples for streamed and unstreamed
reads and writes.
Nonstreamed Read
The following code example demonstrates how to obtain data from an internal LOB
(in this example, a BLOB) that is not null by using a nonstreamed read:
ResultSet *rset=stmt->executeQuery("SELECT ad_composite FROM print_media
WHERE product_id=6666");
while(rset->next())
5-10 Oracle C++ Call Interface Programmer’s Guide
Note: The definition of a transaction within which an open LOB
value must be closed is one of the following:
■ Between SET TRANSACTION and COMMIT
■ Between DATA MODIFYING DML or SELECT ... FOR
UPDATE and COMMIT
■ Within an autonomous transaction block