CHAR or VARCHAR

two questions.
When should I use one, and when the other?
Which is the limit on CHAR(n) and VARCHAR(n)?

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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