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From: pgsql-sql <pgsql-sql@fc.emc.com.ph>
To: pgsql-sql@postgresql.org
To: craig.may@s2.enthdimension.com.au
Subject: Re: Large Objects
Date: Tue, 24 Oct 2000 11:29:31 +0800
Message-ID: <fc.000f56720076f41a000f56720076f41a.76f4d3@fc.emc.com.ph> (raw)


FROM test.pl of DBD-Pg-0.93.tar ...

######################### test large objects

# create large object from binary file

my ($ascii, $pgin);
foreach $ascii (0..255) {
    $pgin .= chr($ascii);
};

my $PGIN = '/tmp/pgin';
open(PGIN, ">$PGIN") or die "can not open $PGIN";
print PGIN $pgin;
close PGIN;

# begin transaction
$dbh->{AutoCommit} = 0;

my $lobjId;
( $lobjId = $dbh->func($PGIN, 'lo_import') )
    and print "\$dbh->func(lo_import) ...... ok\n"
    or  print "\$dbh->func(lo_import) ...... not ok\n";

# end transaction
$dbh->{AutoCommit} = 1;

unlink $PGIN;


# blob_read

# begin transaction
$dbh->{AutoCommit} = 0;

$sth = $dbh->prepare( "" ) or die $DBI::errstr;

my $blob;
( $blob = $sth->blob_read($lobjId, 0, 0) )
    and print "\$sth->blob_read ............ ok\n"
    or  print "\$sth->blob_read ............ not ok\n";

$sth->finish or die $DBI::errstr;

# end transaction
$dbh->{AutoCommit} = 1;


# read large object using lo-functions

# begin transaction
$dbh->{AutoCommit} = 0;

my $lobj_fd; # may be 0
( defined($lobj_fd = $dbh->func($lobjId, $dbh->{pg_INV_READ}, 'lo_open')) )
    and print "\$dbh->func(lo_open) ........ ok\n"
    or  print "\$dbh->func(lo_open) ........ not ok\n";

( 0 == $dbh->func($lobj_fd, 0, 0, 'lo_lseek') )
    and print "\$dbh->func(lo_lseek) ....... ok\n"
    or  print "\$dbh->func(lo_lseek) ....... not ok\n";

my $buf = '';
( 256 == $dbh->func($lobj_fd, $buf, 256, 'lo_read') )
    and print "\$dbh->func(lo_read) ........ ok\n"
    or  print "\$dbh->func(lo_read) ........ not ok\n";

( 256 == $dbh->func($lobj_fd, 'lo_tell') )
    and print "\$dbh->func(lo_tell) ........ ok\n"
    or  print "\$dbh->func(lo_tell) ........ not ok\n";

( $dbh->func($lobj_fd, 'lo_close') )
    and print "\$dbh->func(lo_close) ....... ok\n"
    or  print "\$dbh->func(lo_close) ....... not ok\n";

( $dbh->func($lobjId, 'lo_unlink') )
    and print "\$dbh->func(lo_unlink) ...... ok\n"
    or  print "\$dbh->func(lo_unlink) ...... not ok\n";

# end transaction
$dbh->{AutoCommit} = 1;


# compare large objects

( $pgin cmp $buf and $pgin cmp $blob )
    and print "compare blobs .............. not ok\n"
    or  print "compare blobs .............. ok\n";

#########################


craig.may@s2.enthdimension.com.au writes:
>Hi,
>
>Could someone please provide a demo of creating the type "Lo".
>
>Regards,
>Craig May
>
>Enth Dimension
>http://www.enthdimension.com.au

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