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#!/usr/bin/perl -w
use strict;
use DBI;
use DBD::Pg;
my $dsn = "dbname=p1";
my $dbh = DBI->connect('dbi:Pg:dbname=p1', undef, undef, { AutoCommit => 1 });
my $buf = 'abcdefghijklmnopqrstuvwxyz' x 400;
my $id = write_blob($dbh, undef, $buf);
my $dat = read_blob($dbh, $id);
print "Done\n";
sub write_blob {
my ($dbh, $lobj_id, $data) = @_;
# begin transaction
$dbh->{AutoCommit} = 0;
# Create a new lo if we are not passed an lo object ID.
unless ($lobj_id) {
# Create the object.
$lobj_id = $dbh->func($dbh->{'pg_INV_WRITE'}, 'lo_creat');
}
# Open it to get a file descriptor.
my $lobj_fd = $dbh->func($lobj_id, $dbh->{'pg_INV_WRITE'}, 'lo_open');
$dbh->func($lobj_fd, 0, 0, 'lo_lseek');
# Write some data to it.
my $len = $dbh->func($lobj_fd, $data, length($data), 'lo_write');
die "Errors writing lo\n" if $len != length($data);
# Close 'er up.
$dbh->func($lobj_fd, 'lo_close') or die "Problems closing lo object\n";
# end transaction
$dbh->{AutoCommit} = 1;
return $lobj_id;
}
sub read_blob {
my ($dbh, $lobj_id) = @_;
my $data = '';
my $read_len = 256;
my $chunk = '';
# begin transaction
$dbh->{AutoCommit} = 0;
my $lobj_fd = $dbh->func($lobj_id, $dbh->{'pg_INV_READ'}, 'lo_open');
$dbh->func($lobj_fd, 0, 0, 'lo_lseek');
# Pull out all the data.
while ($dbh->func($lobj_fd, $chunk, $read_len, 'lo_read')) {
$data .= $chunk;
}
$dbh->func($lobj_fd, 'lo_close') or die "Problems closing lo object\n";
# end transaction
$dbh->{AutoCommit} = 1;
return $data;
}
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