Re: Why all the max length constraints?

"Tony Andrews" <andrewst_at_onetel.com> wrote in message news:1148825050.244157.7160_at_i40g2000cwc.googlegroups.com...
> dawn wrote:
> > As soon as I understand why those max length constraints on attributes
> > are part of every such implementation, then I will have learned the
> > answer to my question and will be satisfied.

> You mean: why do all SQL DBMSs /allow/ you to constrain the max length
> of an attribute? You know they do not /force/ you to.

Why they /force/ you to have a max length of an index key ? Why they /force/ you to have indices ?

> I can
> > definitely understand that if we are printing actual paper checks using
> > courier of a fixed size then we have only so many characters we can
> > print. If that is all this is about, then we need it far less today
> > than we once did and we should be very careful when we decide to put
> > that constraint on the database rather than determining how to handle
> > the representation. If another piece of data should be collected on
> > how to abbreviate the actual value in case of less space, fine. If it
> > is not a form like that, but simply a report, then wrap the data,
> > rather than truncating it, and you can have full values in fixed length
> > output. Again, that is a representation issue.

> I wasn't talking about paper, I was talking about programming and
> memory.

Ah, but memory is virtually unlimited these days.

> > If the reason these DBMS's do this is for me, the app developer, then
> > thanks, but I prefer not to use that feature when the data values are
> > conceptually of unlimited length.

> So don't. Use them when data values are of conceptually limited
> length.

I can't. Received on Wed May 31 2006 - 09:31:15 CEST