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From Susan Cline <home4...@pacbell.net>
Subject RE: Using JPOX JDO with Derby
Date Fri, 10 Mar 2006 18:06:11 GMT
--- Michael Segel <msegel@segel.com> wrote:

[snip]
> 
> Your cities table doesn't map to your flights table.
> 
> Note: you id airports via their 3 letter code.
> But you don't map this to the cities.
> 
> While this is an example, note that some cities have multiple airports.
> (NY has 3*, Chicago has 2 )
> 
> Either you goofed on the Airport being a VARCHAR() or you just forgot it....

> > -----Original Message-----
> > From: Susan Cline [mailto:home4slc@pacbell.net]

[snip]

> > 
> > I wrote a "cook-book" like paper which is now on the Derby
> > web site (thanks Jean!) which shows how to use JPOX JDO 1.1
> > (the reference implementation of the JDO 2.0 specification)
> > with Derby.
> > 
> >   http://db.apache.org/derby/integrate/JPOX_Derby.html
> > 

Michael,

APP.CITIES.AIRPORT gets joined to APP.FLIGHTS.ORIG_AIRPORT, which is a CHAR(3), 
so you're right, it would be cleaner to make that column in APP.CITIES a CHAR(3). 
This example was more focused on the JPOX JDO technology than on the database 
schema, but thanks for noticing and making the suggestion. 

I'll work it into the next version of the example.

Susan

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