El Mié 21 Mar 2001 22:21, Stephan Szabo escribió:
> On Wed, 21 Mar 2001, Martin A. Marques wrote:
> > two questions.
> > When should I use one, and when the other?
>
> Almost always varchar() unless you know that your
> input is of constant size.
How does performace look when doing lots of searches on a VARCHAR column with
respect of a CHAR column? That is my main concern.
I mean, what if I have to do lots of queries with LIKEs on that column?
> > Which is the limit on CHAR(n) and VARCHAR(n)?
>
> In 7.0.x and earlier, there's an row limit
> for all values in a row which defaulted to 8k (just
> below technically i believe) but could be raised
> at compile time to 32k.
> All fields in the row had to fit in that 8-32k.
> So you'd have to figure the limit out based on the
> other fields.
>
> In 7.1(currently in beta), long values can be stored
> outside that so you have more of a number of columns
> limit rather than a per value limit. Technically,
> it's probably still not a great idea to be sticking
> megs in there for performance reasons.
I can't believe that there is no limit. You mean that I put this:
VARCHAR(1000000000000000000000000000000000)
?
Saludos... :-)
--
System Administration: It's a dirty job,
but someone told me I had to do it.
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Martín Marqués email: martin@math.unl.edu.ar
Santa Fe - Argentina http://math.unl.edu.ar/~martin/
Administrador de sistemas en math.unl.edu.ar
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