Christophe Barbe wrote: >I am looking about experienced pros and cons on the use of VARCHAR. My >understanding is that, except if you know that each time the text will >have the same length, VARCHAR is better. This seems a bit too perfect to >be true. > You do not have to use all the chars ... if you have a field that is CHAR(100), it will always use 100 bytes, but you can insert a 12 byte value (or none) into it anyway. If you have lots of disk space, just use CHAR and ignore VARCHAR if you want. If you want to conserve disk space, VARCHAR will save you some (maybe lots).
>Also I am wondering about the tradeof between using a separate table for >rare comments (ie. most of the time empty) and the use of a VARCHAR >which use only one byte to store an empty comment. > > It depends on your queries; if you don't ask for the large blob often then you'll get better performance with seperate tables. Some of the gurus around here might have additional comments ... PS, SQL QUERYs are fun ... (anti-spam anti-filter) -- Michael T. Babcock C.T.O., FibreSpeed Ltd. http://www.fibrespeed.net/~mbabcock --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
