OCCI Clob.write problem

Question

hi
i am new to occi
i have tested my application and insert data to my tables ;
I have a field in my table which its type is clob and a procedure for inserting in that table
when i test procedure with stmt.setString (for the clob field) I have no problem for inserting
but when using stmt->setClob , there is exception ora-22275
my code is like this:
Clob C(conn);
C.setEmpty();
C.write(4,"test",4);
stmt->setClob(1,C);
stmt->executeUpdate();
whats wrong?
error message is about problem in occi::clob::write

Answer 1

Hi,
Because LOBs use what are known as locators, you can't just create the clob in client code like that and insert it into the database.
The database won't "know about" the locator and will raise the ORA-22275 error (as you have discovered).
What you need to do is initialize the clob as noted in the Clob Class documentation notes. See here for example:
http://download.oracle.com/docs/cd/B28359_01/appdev.111/b28390/reference009.htm#i1118691
An uninitialized CLOB object can be initialized by:
* The setEmpty() method. The CLOB can then be modified by inserting this CLOB into the table and retrieving it using SELECT ... FOR UPDATE....
< emphasis added >
So, essentially, you set the clob to empty, insert it into the table, then using "select for update" you get the clob (locator) back. You need to use "select for update" and not just a regular select. You can then modify the empty clob (be sure to commit when done).
For an example of this, see the Oracle 10g Release 1 Demos from here:
http://www.oracle.com/technology/sample_code/tech/occi/index.html
Regards,
Mark