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From:Krishna Chandra Prajapati Date:September 10 2008 4:52am
Subject:Re: DATATYPES
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Thanks a lot.

On Tue, Sep 9, 2008 at 7:35 PM, Martijn Tonies <m.tonies@stripped> wrote:

>
>
> > You pretty much answered your own question. A char will always use the
> > same amount of space (the max size), regardless of how little data you
> > put in it. A varchar will only use enough space to store the data, so
> > the amount of space used for each record will be different. You can
> > also specify a max size for varchar. Text is like varchar, but with a
> > "fixed" max size of 65,000 characters.
>
> That's actually not entirely true :-)
>
> Yes, it holds true for MySQL because of it's rather crappy implementation
> on data storage in the current engines.
>
> There's a -logical- difference between CHAR and VARCHAR in which
> CHAR always adds padded spaces and VARCHAR strips these.
>
> However, as I said, this is a -logical- difference. The space that is
> needed
> for storage is a physical issue which is implementation defined. Another
> storage engine can store CHAR and VARCHAR the same if it likes to do
> that and so the space requirements can be (more or less) the same.
>
> To answer this question truely, you need to know what storage engine is
> used AND you need to know how the storage is implemented.
>
> > > char limit 255 character fixed length
> > > varchar limit 65,000 character variable length
> > > text limit 65,000 character variable length.
>
>
> Martijn Tonies
> Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle &
> MS SQL Server
> Upscene Productions
> http://www.upscene.com
> My thoughts:
> http://blog.upscene.com/martijn/
> Database development questions? Check the forum!
> http://www.databasedevelopmentforum.com
>
>
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>


-- 
Krishna Chandra Prajapati

Thread
DATATYPESKrishna Chandra Prajapati9 Sep
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