BLOB support problem !!!!

From: GP <pagomen(at)csd(dot)uoc(dot)gr>
To: pgsql-jdbc(at)postgresql(dot)org, GP <pagomen(at)csd(dot)uoc(dot)gr>
Subject: BLOB support problem !!!!
Date: 2004-06-23 11:30:30
Message-ID: 40D969D6.1070900@csd.uoc.gr
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Hi all,

I have some java code to r/w a binary file in the database.
According to the tutorial
(http://doc.postgresintl.com/jdbc/ch08.html#jdbc-binary-data-example)
there are 2 ways:

1) To use a 'bytea' type in the database

CREATE TABLE images (imgname text, img bytea);

File file = new File("myimage.gif");
FileInputStream fis = new FileInputStream(file);
PreparedStatement ps = conn.prepareStatement("INSERT INTO images VALUES (?, ?)");
ps.setString(1, file.getName());
ps.setBinaryStream(2, fis, file.length());
ps.executeUpdate();
ps.close();
fis.close();

2) Use the LargeObject API and the 'oid' type in the databse

CREATE TABLE imageslo (imgname text, imgoid oid);

// All LargeObject API calls must be within a transaction block
conn.setAutoCommit(false);

// Get the Large Object Manager to perform operations with
LargeObjectManager lobj = ((org.postgresql.PGConnection)conn).getLargeObjectAPI();

// Create a new large object
int oid = lobj.create(LargeObjectManager.READ | LargeObjectManager.WRITE);

// Open the large object for writing
LargeObject obj = lobj.open(oid, LargeObjectManager.WRITE);

// Now open the file
File file = new File("myimage.gif");
FileInputStream fis = new FileInputStream(file);

// Copy the data from the file to the large object
byte buf[] = new byte[2048];
int s, tl = 0;
while ((s = fis.read(buf, 0, 2048)) > 0) {
obj.write(buf, 0, s);
tl += s;
}

// Close the large object
obj.close();

// Now insert the row into imageslo
PreparedStatement ps = conn.prepareStatement("INSERT INTO imageslo VALUES (?, ?)");
ps.setString(1, file.getName());
ps.setInt(2, oid);
ps.executeUpdate();
ps.close();
fis.close();

I tried both of them BUT
The first one throw an OutofMemoryException for files > 1.5 Mbyte (is
this some kind of bug ??)
And the second one doesn't throw any Exception or Error but it does NOT
write anything in the database !!

I did something wrong ?
Has anyone experience in r/w blobs in postgres through jdbc ??

Thanks in advance
George

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