Aware of that, but char brings you certain performance benefits that are good to know about if you need every last drop of juice :-)
On 11/11/09, Martijn Tonies <m.ton...@upscene.com> wrote: > > >> Your mail suggests that you *are* seeing a difference, though. What >> are you seeing? > > What I was saying, is that VARCHAR takes up space "l" (= length) > of the data plus 1 or 2 bytes to store the length, while CHAR takes > up the full space of the -defined- column size. > > This is rather wasteful when storing CHAR data that doesn't take up > the full available space (as this is padded with spaces up to the defined > length) and is a storage engine "feature" ;-) > > With regards, > > Martijn Tonies > Upscene Productions > http://www.upscene.com > > Download Database Workbench for Oracle, MS SQL Server, Sybase SQL > Anywhere, MySQL, InterBase, NexusDB and Firebird! > > Database questions? Check the forum: > http://www.databasedevelopmentforum.com > > >> On 11/11/09, Martijn Tonies <m.ton...@upscene.com> wrote: >>>>You have stumbled across the secret. No, there is no difference at >>>>all as the calculations suggested here confirm. >>>> >>>>http://dev.mysql.com/doc/refman/5.1/en/storage-requirements.html >>> >>> Note: as you can see in the above, CHAR data DOES take up room for it's >>> full size, stupidly enough. >>> >>> On Tue, Nov 10, 2009 at 6:37 PM, Waynn Lue <waynn...@gmail.com> wrote: >>>> Hey all, >>>> >>>> I was building a table for storing email addresses today and ran into an >>>> issue that I couldn't find an answer for using Google. If I declare the >>>> column as a VARCHAR (this is an InnoDB table), does it matter what size >>>> I >>>> declare it as if it's between 1 and 255? I know there's an extra byte of >>>> storage once it goes above 255 because of the length, but is there a >>>> storage >>>> difference between VARCHAR(100) and VARCHAR(255)? Obviously there's a >>>> functional difference in what gets cut off when I try to store into that >>>> table, but is that the only difference? >>> >>> With regards, >>> >>> Martijn Tonies >>> Upscene Productions >>> http://www.upscene.com >>> >>> Download Database Workbench for Oracle, MS SQL Server, Sybase SQL >>> Anywhere, MySQL, InterBase, NexusDB and Firebird! >>> >>> Database questions? Check the forum: >>> http://www.databasedevelopmentforum.com >>> >>> >>> -- >>> MySQL General Mailing List >>> For list archives: http://lists.mysql.com/mysql >>> To unsubscribe: http://lists.mysql.com/mysql?unsub=vegiv...@tuxera.be >>> >>> > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/mysql?unsub=vegiv...@tuxera.be > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
