From: | "David Wall" <d(dot)wall(at)computer(dot)org> |
---|---|
To: | "Marc G(dot) Fournier" <scrappy(at)postgresql(dot)org> |
Cc: | <pgsql-jdbc(at)postgresql(dot)org> |
Subject: | Re: types used for JDBC BLOB and CLOB? |
Date: | 2004-08-23 22:18:13 |
Message-ID: | 089c01c4895f$14ff2360$3201a8c0@rasta |
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Thread: | |
Lists: | pgsql-jdbc |
If you want to use the BLOB JDBC calls, you will use the OID type for the
field in your table schema.
You do NOT need to use the lo_ routines since they will be called for you if
you use the JDBC BLOB calls.
David
----- Original Message -----
From: "Marc G. Fournier" <scrappy(at)postgresql(dot)org>
To: "Barry Lind" <blind(at)xythos(dot)com>
Cc: "Marc G. Fournier" <scrappy(at)postgresql(dot)org>; <pgsql-jdbc(at)postgresql(dot)org>
Sent: Monday, August 23, 2004 3:06 PM
Subject: Re: [JDBC] types used for JDBC BLOB and CLOB?
>
> k .. I'm obviously missing something, and having never used BLOBs before,
> I'm not surprised ...
>
> Looking at:
>
> http://www.postgresql.org/docs/7.4/static/lo-implementation.html
>
> It states:
>
> "The large object implementation breaks large objects up into "chunks" and
> stores the chunks in rows in the database."
>
> When I create my schema for this, what type do I assign the field? Or is
> there a special 'table' created when you do the lo_creat to store the
> BLOBs in? (looking at docs, which references the libpq library vs JDBC,
> sorry)
>
> For instance, I notice in:
>
> http://www.postgresql.org/docs/7.4/static/lo-interfaces.html
>
> "Oid lo_creat(PGconn *conn, int mode);"
>
> So, lo_creat returns an OID ... is that what I'd store in a table, and
> when I needed the value, would call lo_open to actually access it as I
> need?
>
> The part that is confusing me is the point about 'chunks' above ...
from
> that, it seems that the data is stored in table within the database ...
> but if so, what type does one define to store it in? how would a
> 'pg_dump' show the schema?
>
> Hopefully this explains a bit better my confusion here :(
>
>
> On Mon, 23 Aug 2004, Barry Lind wrote:
>
> > Marc,
> >
> > The answer is it depends, but if they intend to use the jdbc BLOB/CLOB
> > interface it is server side LargeObjects, not bytea. However you can
> > use bytea, but then you need to use the get/setXXXStream() interfaces.
> >
> > Thanks,
> > --Barry
> >
> > -----Original Message-----
> > From: Marc G. Fournier [mailto:scrappy(at)postgresql(dot)org]
> > Sent: Monday, August 23, 2004 11:52 AM
> > To: Barry Lind
> > Cc: Marc G. Fournier; pgsql-jdbc(at)postgresql(dot)org
> > Subject: RE: [JDBC] types used for JDBC BLOB and CLOB?
> >
> >
> > 'k, I believe what the client is wanting to know is what the storage
> > type would be on the backend, that the would BLOB/CLOB map to ... bytea?
> >
> > On Mon, 23 Aug 2004, Barry Lind wrote:
> >
> >> Marc,
> >>
> >> If you are specifically talking about the JDBC types BLOB and CLOB
> >> those classes use the server LargeObject interface. If you are
> >> speaking generically about support for large objects then the jdbc
> >> driver supports the bytea datatype for the get/setBinaryStream()
> >> methods. So the answer is "it depends", on how you use the driver.
> >> The specifics for supporting binary objects are documented in a
> >> section on this topic in the postgresql jdbc driver documentation
> > chapter.
> >>
> >> Thanks,
> >> --Barry
> >>
> >> -----Original Message-----
> >> From: Marc G. Fournier [mailto:scrappy(at)postgresql(dot)org]
> >> Sent: Monday, August 23, 2004 8:44 AM
> >> To: pgsql-jdbc(at)postgresql(dot)org
> >> Subject: [JDBC] types used for JDBC BLOB and CLOB?
> >>
> >>
> >> Just been asked this, and I'm not sure of the answer ... based on
> >> reading the docs on bytea, I'm assuming that it is such, but can
> >> someone please confirm?
> >>
> >> Thanks ...
> >>
> >> ----
> >> Marc G. Fournier Hub.Org Networking Services
> >> (http://www.hub.org)
> >> Email: scrappy(at)hub(dot)org Yahoo!: yscrappy ICQ:
> >> 7615664
> >>
> >> ---------------------------(end of
> >> broadcast)---------------------------
> >> TIP 7: don't forget to increase your free space map settings
> >>
> >>
> >
> > ----
> > Marc G. Fournier Hub.Org Networking Services
> > (http://www.hub.org)
> > Email: scrappy(at)hub(dot)org Yahoo!: yscrappy ICQ:
> > 7615664
> >
> >
>
> ----
> Marc G. Fournier Hub.Org Networking Services
(http://www.hub.org)
> Email: scrappy(at)hub(dot)org Yahoo!: yscrappy ICQ:
7615664
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
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