Received: from pain.crcg.edu (pain.crcg.edu [207.252.32.124])
	by hub.org (8.9.3/8.9.3) with ESMTP id LAA59843
	for <pgsql-general@hub.org>; Tue, 22 Jun 1999 11:42:35 -0400 (EDT)
	(envelope-from szimmert@crcg.edu)
Received: from crcg.edu (wheel.crcg.edu [207.252.32.136])
	by pain.crcg.edu (8.9.1b+Sun/8.9.1) with ESMTP id LAA14826;
	Tue, 22 Jun 1999 11:39:42 -0400 (EDT)
Message-ID: <376FD814.23CE0333@crcg.edu>
Disposition-Notification-To: Steffen Zimmert <szimmert@crcg.edu>
Date: Tue, 22 Jun 1999 11:38:12 -0700
From: Steffen Zimmert <szimmert@crcg.edu>
Organization: Fraunhofer CRCG, Inc.
X-Mailer: Mozilla 4.61 [en] (WinNT; I)
X-Accept-Language: en
MIME-Version: 1.0
To: PostgreSQL General Mailing List <pgsql-general@hub.org>,
	pgsql-interfaces@postgreSQL.org
Subject: JDBC:Using Large Objects
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Hi,

I am trying to store some Java objects in the PostgreSQL database
system. The version of PostgreSQL is 6.4.2 running on a linux sparc
machine. The JDBC driver is the one I found in the src/interfaces/jdbc
directory.

First of all I tried to use the example provided on page 167 of the JDCB
interface guide but the setBinaryStream() method is not supported by the
driver yet. So I wanted to store the objects as an array of bytes.
Here's the code I am using at the moment:

I created the associated database table with the following statement:
create table images (imgname name, imgoid oid);

// Load the driver
Class.forName("postgresql.Driver");
    
// Connect to database
System.out.println("Connecting to Database URL = " + url);
db = DriverManager.getConnection(url, usr, pwd);
    
System.out.println("Connected...Now creating a statement");
TestObject testObject = new TestObject(1);
byte[] objBytes = objectToBytes(testObject);
System.out.println("Bytes: " + objBytes.length);
	
// Create PreparedStatement
PreparedStatement ps = db.prepareStatement("Insert into database values
(?,?)");
ps.setString(1,"TEST");
ps.setBytes(2,objBytes);
ps.executeUpdate();
ps.close();
		        
Every time when I execute my little program I receive the following
exception:
PostgreSQL basic test v6.3 rev 1
Connecting to Database URL = jdbc:postgresql://hornbill/foo
Connected...Now creating a statement
Bytes: 42
Exception caught.
java.sql.SQLException: IOError while reading from backend:
java.io.IOException: The backend has broken the connection. Possibly the
action you have attempted has caused it to close.
java.sql.SQLException: IOError while reading from backend:
java.io.IOException: The backend has broken the connection. Possibly the
action you have attempted has caused it to close.
	at postgresql.PG_Stream.ReceiveChar(PG_Stream.java:183)
	at postgresql.fastpath.Fastpath.fastpath(Compiled Code)
	at postgresql.fastpath.Fastpath.fastpath(Fastpath.java:185)
	at postgresql.largeobject.LargeObject.write(LargeObject.java:147)
	at postgresql.PreparedStatement.setBytes(PreparedStatement.java:295)
	at basic.<init>(basic.java:45)
	at basic.main(basic.java:107)


In general is it possible to use the LargeObject interface with the JDBC
driver or is it not supported yet????
-- 
Best Regards,
Steffen Zimmert


Steffen Zimmert
Fraunhofer Center for Research in Computer Graphics
Providence, Rhode Island, USA
email: szimmert@crcg.edu