Tue Jun 4 12:17:20 MDT 2013
where Customer.Cust_ID NOT IN
(select distinct Cust_ID from Invoice where where
Invoice_Date between '1 Jan 1999' and '1 Jan 2000')
The additional UNION clause can get very, very cumbersome on a complex
statement. Postgresql is supposed to support this in version 7.1.
5) JDBC suport
We do Java Servlet development so this is a requirement for us. Postgresql
supports this, but the driver is kind of shaky in some respects.
If you need it, there is no substitute. A friend of mine wrote an app for a
company with 16 branch offices and multiple travelling salesmen. Using
replication, the sales people can have a complete disconnected copy of the
database on their laptop at all times without requiring a LAN/WAN/Internet
connection. When they reconnect, changes that they make to the data are
replicated up to their parent office, and from there up to the headquarters.
SQL Anywhere supports replication in such a way that only each branch's data
is replicated downwards to it. Some large commercial apps like Siebel use
SQL Anywhere for this purpose. It's also useful when you need remote data,
but you are dependent upon an unstable connection. I.E. you have a
monitoring system stuck on a hilltop someplace that needs the database to
perform lookups and also log information. Using a replication system, it's
transparent to your application when the WAN link goes down. When the WAN
link comes up, the database just re-synchronizes. You can do this yourself
but it takes code and is hard to get right.
> -----Original Message-----
> From: bill ehlert [mailto:bill_ehlert at yahoo.com]
> Sent: Thursday, June 29, 2000 12:52 AM
> To: George Sexton
> Subject: RE: [lug] Databases
> ** would you mind posting a short, general
> discussion of the nature and usefulness
> of each of those 6 features?
> 1 or 2 i think i understand, but ...
> what the heck is the use of replicating
> data on various machines, other than
> perhaps super-backup???
> also, hope you'll take up the offer
> to do a presentation on SQLA
> --- George Sexton <gsexton at mhsoftware.com> wrote:
> > We have used Sybase SQL Anywhere on Linux. It's
> > less expensive than Oracle,
> > but has the features that I think make up an
> > industrial strength DB:
> > Declarative Referential Integrity
> > True Transaction Log
> > Stored Procedure Language
> > Outer Joins
> > JDBC Support
> > In addition to these features, perhaps the
> > killer feature of SQLA is the
> > replication.
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