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

Thank you Marco Bizzarri.

My solution would be C API.

Thanks for you prompt response.

:)
Purusothaman A

On 9/11/06, Marco Bizzarri <marco(dot)bizzarri(at)gmail(dot)com> wrote:
>
> On 9/11/06, Purusothaman A <purusothaman(dot)a(at)gmail(dot)com> wrote:
> > Hi Marco Bizzarri and Martijn van Oosterhout,
> >
> >
> > Thanks for your valuable reply.
> >
> > I am trying to execute all query from VC++ through
> > CDatabase::ExecuteSQL(sQueryString) function call.
> >
> > ie, via programming, not by manual entering query statements.
> > so, in my situation I can construct a string and pass on to this
> function to
> > execute the query string.
> >
> > Whatever the string I pass to ExecuteSQL() function, gets executed and I
> > cannot get any result retured from the passed query string [like OID -
> > 198705, from lo_create()].
>
> I'm not an expert in VC++. I think you should obtain some sort of
> ResultSet object. You could then check that.
>
>
>
> > Now, can you suggest me how to achieve it?
> >
> > And one more clarification, what is the value 131072? How can I get this
> > vlaue?
>
> This is actually 0x20000 value in decimal. Check large object
> interface in postgresql documentation (C API).
>
> > According to PostgreSQL documentation, they gave C Syntax as client side
> > function.
> >
> > Should I use those C API calls?
>
> If you're working from inside C, you can check:
>
> http://www.postgresql.org/docs/8.1/staticI /lo-interfaces.html
>
> Regards
> Marco
>
>
> > :)
> > Purusothaman A
> >
> >
> > On 9/11/06, Marco Bizzarri <marco(dot)bizzarri(at)gmail(dot)com > wrote:
> > > 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.
> > > >
> > > >
> > > > -----BEGIN PGP SIGNATURE-----
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> > > > ijq1n/SgAlwIiEgDI6zfICg=
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> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > --
> > > Marco Bizzarri
> > > http://notenotturne.blogspot.com/
> > >
> >
> >
>
>
> --
> Marco Bizzarri
> http://notenotturne.blogspot.com/
>