Re: Distributed database question

"Jim Kennedy" <kennedy-down_with_spammers_at_no_spam.comcast.net> wrote in message news:<mVsab.507793$Ho3.85596_at_sccrnsc03>...
> No, move all the data to 1 machine and have 3 schemas. Then you can create
> a view that joins the 3 schemas(1 view for each table). The entity bean
> approach is a Java programmer with a hammer that thinks everything is a
> nail.]
> Jim
>
> --
> Replace part of the email address: kennedy-down_with_spammers_at_attbi.com
> with family. Remove the negative part, keep the minus sign. You can figure
> it out.
> "J Goldman" <jason_at_fc.hp.com> wrote in message
> news:3f69d03f$1_at_usenet01.boi.hp.com...
> > Well, thanks for the vote of confidence. I appreciate your point that
> > this approach doesn't seem doomed to success. With that in mind,
> > can you offer any contructive suggestion on how I might provide
> > global access to this data? My other main thought has been to create
> > a set of entity EJBs local to each machine, along with a set of global
> > session beans. The global session beans would use something like a
> > dbhost parameter (where appropriate) to guide which db should be
> > read. Generic requests would query all of the DBs.
> >
> > Jason
> > jason_at_fc.hp.com
> >
> >
> > "Sybrand Bakker" <postbus_at_sybrandb.demon.nl> wrote in message
> > news:a20d28ee.0309180357.54887fa3_at_posting.google.com...
> > > "J Goldman" <jason_at_fc.hp.com> wrote in message
 news:<3f68c63a$1_at_usenet01.boi.hp.com>...
> > > > A pointer in the right direction would be greatly appreciated.
> > > >
> > > > Jason
> > > > jason_at_fc.hp.com
 

> > > > I would like to set up a distributed database system with location
> > > > transparency and a shared schema (i.e. horizontal fragmentation).
 I'll
> > > > provide a little more context: I have three databases, running on
 separate
> > > > systems, all of which use the identical schema. So, each has entries
> in
> a
> > > > table "foo", which are unique. I'd like to provide a global access to
 this
> > > > data, so a client can effectively query the set of databases. So,
 asking
> > > > for all entries in the "foo" table would retrieve the contents of
 db1.foo,
> > > > db2.foo, and db3.foo. Ideally, when all is said and done, I'm
> planning
> to
> > > > wrap this in an enterprise java bean to provide an object interface.
> > > >
> > > Your scenario has 'DISASTER AHEAD' inscribed all over it. You would be
> > > better off by using a few 1000 of voting machines using punchcards.
> > > Your approach would require to use UNIONs for everything, which means
> > > the database will resort to full table scan and sorting for ALL sql
> > > you sunmit.
> > > Need I say more? Why do you want this? Are you up for a career move,
> > > or do you like getting sacked by HP?
> > >
> > > Sybrand Bakker
> > > Senior Oracle DBA
> >
> >
If the DBS have to be in different locations, dosn't sound like RAC would do you much good. What about doing all the work in the Middle Tier and have your java app connect to all three servers and launch a seperate query to each one? The oracle app server 9iAS should be able to deal with all this easily (have to spend money though if you don't have it) as it's meant to connect to many nodes. I would be leary of links and union which may come to a screaching hault if one of the DBs is unavailable.

Not sure how much data you have or how often it gets inserts and updates, or how up the the minute data your query requires, but look into materialized views if data and activity set is not too large or you could use replication to have at least one database with all 3 DBs data (kind of a data mart approach). Received on Fri Sep 19 2003 - 17:43:39 CEST