Absolutely. Big bridge or small bridge, if it fails you fall in the water.
It looks as if the bridge in Minneapolis failed because construction
workers moved tons of repaving material onto part of it and overstressed
that section. A few calculations could have saved the catastrophe.
I saw an estimate that software errors cost just the US more than $100
billion per year. That is equivalent to more than 5% of the entire UK
GDP. Doesn't it make sense to try to build software which works to
design rather than trying alternatives until one which does not fail
eventuates?
Also note what early researchers in proof of software accuracy pointed
out. Testing only finds bugs, it does not establish the correctness of
a program. Only an appropriate design methodology can hope to establish
correct behaviour of the program.
RB Smissaert wrote:
Poor comparison in this case.
Are you going to make a mathematical model when you got a little stream to
cross and you have a few available planks to do it?
RBS
-----Original Message-----
From: John Stanton [mailto:[EMAIL PROTECTED]
Sent: 05 August 2007 16:43
To: sqlite-users@sqlite.org
Subject: Re: [sqlite] Re: Re: Re: Re: Re: Re: Re: How does SQLite choose the
index?
We learn mathematics etc so that we can make numerical models which give
us design information. Imagine trying to build every combination of a
bridge to settle on a design!
Make a mathematical model and get it close to optimal at the first attempt.
RB Smissaert wrote:
Yes, I suppose you are right there.
I will see if I can put together a report that runs all possible types of
queries (sequentially) and then see if I have left anything out that would
cause problems.
RBS
-----Original Message-----
From: Gerry Snyder [mailto:[EMAIL PROTECTED]
Sent: 05 August 2007 03:35
To: sqlite-users@sqlite.org
Subject: Re: [sqlite] Re: Re: Re: Re: Re: Re: Re: How does SQLite choose
the
index?
RB Smissaert wrote:
.... I think an application that
would produce all the needed indexes based on the table and all the
possible
queries would be helpful. Anybody done such an app?
_All_ possible queries? Not practical for any significant number of
columns. N factorial gets big fast.
The indexes would be much larger than the data base itself.
I'm afraid you are going to have to settle for doing an intelligent
design of the data base.
Gerry
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