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From "1075244@imap.gmx.net" <1075...@imap.gmx.net>
Subject Re: Oracle 9i BLOB malfunction / 4k mystery (issue OJB170)
Date Thu, 15 May 2003 11:24:41 GMT
Folks,

if I get this right, we still don't have a *real* solution to this, do we?
I found that Per-Olof's CLOB patch for using the thin driver made it to the
CVS, but I understand it only fixes this for text < 4 KB, right?

So first of all I thought it was a good idea to enter an issue in the bug
database at http://scarab.werken.com/scarab/issues/id/OJB170 (which became
OJB170).

So to me there are at two questions right now:

1. Is this an OJB bug, an Oracle bug or both?
2. How do we *want* do handle this at all?

What I mean is: To what column type would I map a String object that I
except to grow very large (i.e. some dozends KB of text)?

I might map it to JDBC type CLOB which would be closest to reality but this
will break with a class cast exception (you cannot cast a string to a
java.sql.Clob).

If you map it to anything else such as LONGVARCHAR Oracle will not care but
this will probably break other things.

In fact it might depend on your application what you want back in your bean
when using a CLOB column: You either might want to get a stream you can
read from in some other place or you might want to just get the stuff into
a String and not care about it any more (which would make your application
code much less Oracle specific by the way).

This is essentially two different JDBC types needed for the same type of DB
column. Does the framework support this at all? I am wrong in any
assumption?

Torsten

P.S.: I would like to post this as a comment in Scarab, but I did not yet
find out how to edit the issue. I was able to submit it though. Any help
appreciated.

Original Message:
-----------------
From: Thomas Poeschmann t.poeschmann@exxcellent.de
Date: Mon, 12 May 2003 16:05:08 +0200
To: ojb-dev@db.apache.org
Subject: Re: Oracle 9i BLOB malfunction / 4k mystery


Hi there,

> Michael Mogley wrote:
> Thomas Poeschmann says on the list that he almost has a solution,
> using the above method I presume.

Yes, of course using the SELECT FOR UPDATE. Sorry for promising posting code
but not doing it, but I will try to find it this evening. It is probably
just 
for reference for you, since you already have it.

> Are there other dbmses and drivers that exhibit the same irregular 
> behavior regarding LOBĀ“s.

Not that I know. Sometimes it is different to call one of the methods on a
statement to bring certain Java objects in. For example passing an array in
as
a String. But I have never seen anything hard as Oracle XLOBs ;)

> Unfortunatly, our solution (apart from the the fix submitted) currently 
> consists of changing to the oci driver. Sad but true.

Which has other drawbacks, but well... Other ORM can not handle it either
with
thin, by the way ;)

Kind regards,

Thomas


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