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I am trying to insert a large object in a PostgreSQL database, but am having difficulties finding a graceful way to do this. Note that the included code has been simplified to avoid distractions--I am well aware that I should be addressing possible errors.

System information:

  • perl, version 5.005_03
  • Linux 2.2.14 i686
  • Postgres: 6.5.3
  • DBI: 1.1.3
  • DBD Pg: 0.93

I have created a table with one field, data, which is of type OID. Next I attempt to insert by more or less copying the code on page 153 of 'Programming the Perl DBI':

my $sth = $dbh->prepare("insert into foo(data) values (?);"); $sth->bind_param(1, $value, SQL_LONGVARBINARY); $sth->execute();
I receive a warning that binding the value isn't permitted:
SQL type 1075548612 for 'rc' is not fully supported, bound as VARCHAR +instead at ./1.0 line 122.
Whereupon it fails with a pg_atoi error.

I can insert by writing $value to a file and using the (presumably Postgres-specific) function lo_import:

$dbh->prepare("insert into foo(data) values (lo_import('/tmp/lame'));")
I'm not pleased with this solution because it requires the creation of a temporary file and it seems to undermine the use of DBI to use a database-specific insert.

I imagine some of the problem has to do with the unusual way Postgres deals with large objects. I expected that the Pg DBD would compensate for that, perhaps using lo_import, but accepting the format shown earlier.

The fact that I can't seem to find any documentation mentioning this problem (which I imagine must have occurred before) makes me feel as if I've completely failed to grasp something simple (or that Pg's documentation-dearth is contagious, affecting anything that touches Postgres). Is there a better way to insert a large object in Postgres using DBI? Thanks in advance.


In reply to Difficulty inserting a large object using DBD::Pg by kudra

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    [GotToBTru]: you are correct, choroba, but of course there is no point in doing one without the other
    [GotToBTru]: un less you're working on write-only memory
    [1nickt]: my $x = $aohoaoh->[0]->{' foo'}->[0]->{'bar' }; should work
    [thepkd]: not indexing
    [thepkd]: getting data out of the ds
    [choroba]: it depends. Give more details, please
    [thepkd]: i used a series of {}'s but it dont work
    [choroba]: You need square brackets for arrays
    [GotToBTru]: you can certainly construct a single expression to access any part of the data structure, without using temp variables. but you might make it easier on yourself and any other poor soul who has to understand your code if you do
    [thepkd]: to dereference i mean

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