RE: [xml-dev] XML Database Decision Tree?

[Eric Lemond <elemond@neocore.com>]

I'm struggling with the car analogy a bit.  Help me if I'm
misunderstanding.  

>
>Paul T
>If the process of dismantling / re-assembling is really fast and 
>robust ( no parts would get lost ), the advantage is that you can 
>park 10-1000 times more cars in the same space.  And perhaps 
>have more trees in downtown as a side effect.

XML DBMS's (at least some of them) have a smaller storage footprint than
an indexed RDBMS.  Sometimes it's even smaller than the size of the
original data set.  Therefore, wouldn't the analogy be dismantling the
car and putting all the individual parts in storage containers equal in
size to that necessary for the largest part.  Even though ball bearings
don't need the same amount of space as the car frame, they get that much
space.  In the end, we can store ~1/10 the original number of cars.  I
agree that sometimes it's best to dismantle/reassemble, but I don't
think the storage part fits.

> DanW
> Suppose you want to park your car in a garage while you're not using
> it.  Should you dismantle your car into bolts, ball bearings, shafts,
> cylinders, and so on, putting all the bolts into nice containers
> clearly marked "bolts", all the ball bearings into nice jars labelled
> "ball bearings", and so on?  When you want to take the car out for a
> drive, you just re-assemble it out of all those pieces by joining them
> together.

If I decide I want to put a new stereo in my car, wouldn't I have to
dismantle it, add the stereo and reassemble it in the RDBMS world?  With
an XML DBMS, I just pop in the stereo.  

In addition, in the RDBMS world, if I need two cars (one a fast sports
car to get there quickly and another luxury to give me more amenities) I
need two separate cars.  In the XML DBMS world, I can have one car that
does both.

Do I get it?

Eric Lemond