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.a@gmail.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@svana.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@svana.org> http://svana.org/kleptog/
> > From each according to his ability. To each according to his ability to
> litigate.
>
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.1 (GNU/Linux)
>
> iD8DBQFFBTR4IB7bNG8LQkwRAvhPAJ9KHp9DO1EjPqbkGwBdaSaKx5J90wCfQtZ8
> ijq1n/SgAlwIiEgDI6zfICg=
> =Xk7N
> -----END PGP SIGNATURE-----
>
>
>
>
--
Marco Bizzarri
http://notenotturne.blogspot.com/
