Re: [GENERAL] Problem with lo_export() and lo_import() from remote machine.

From: "Marco Bizzarri" <marco(dot)bizzarri(at)gmail(dot)com>
To: "Purusothaman A" <purusothaman(dot)a(at)gmail(dot)com>
Cc: "Martijn van Oosterhout" <kleptog(at)svana(dot)org>, "Milen A(dot) Radev" <milen(at)radev(dot)net>, pgsql-admin(at)postgresql(dot)org, pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] Problem with lo_export() and lo_import() from remote machine.
Date: 2006-09-11 10:56:11
Message-ID: 3f0d61c40609110356n53e6da12h26d54cb74f448263@mail.gmail.com
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I will try to explain it with a sample session: this is for creating
and writing a blob.

From the psql prompt (> are the commands, the other are the results).

> begin ;
BEGIN;

> SELECT lo_creat(131072) ;
lo_creat
----------
198705
(1 row)
(this is the OID number of the newly created large object).

> select lo_open(198705, 131072) ;
lo_open
---------
0
(1 row)

(this is the file handler which you will use in the operations).

> SELECT lowrite(0, 'aaaa');
lowrite
---------
4
(1 row)

(you wrote 4 character in a large object)

> select lo_close(0);
lo_close
----------
0
(1 row)

(you closed the file).

> commit ;
COMMIT

In this way, you created a new large object, and stored a string of 4
bytes inside of it.

Regards
Marco

On 9/11/06, Purusothaman A <purusothaman(dot)a(at)gmail(dot)com> wrote:
> Thanks Martijn van Oosterhout and Marco Bizzarri.
>
> But, according to syntax of client side lo_import and lo_export, we should
> have 2 variable PGconn (for esatablished connection) and lobjld (imported
> file ID in PostgreSQL).
>
> I don't know how to do this in SQL statements.
>
> pls give me sample client side sql statements.
>
> :)
> Purusothaman A
>
>
> On 9/11/06, Martijn van Oosterhout <kleptog(at)svana(dot)org> wrote:
> >
> On Mon, Sep 11, 2006 at 03:27:09PM +0530, Purusothaman A wrote:
> > Thanks Martijn van Oosterhout,
> >
> > So, I have to write my own wrapper function upon the functions below.
> > 1. Oid lo_import(PGconn *conn, const char *filename);
> > 2. int lo_export(PGconn *conn, Oid lobjId, const char *filename);
>
> Not sure why you need a wrapper (you didn't say which language you were
> using) but those functions work exactly like the version you put in the
> SQL statements, except the filenames are for the client computer with
> client permissions.
>
> Hope this helps,
> --
> Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> > From each according to his ability. To each according to his ability to
> litigate.
>
>
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--
Marco Bizzarri
http://notenotturne.blogspot.com/

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