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char o varchar

P: n/a


Hoii!!

I am creating my struct and I have the question :
What I must use for character fields char or varchar?
Which are the differences? and the better
TIA

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Nov 11 '05 #1
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P: n/a
On Tue, 16 Sep 2003, Edwin Quijada wrote:


Hoii!!

I am creating my struct and I have the question :
What I must use for character fields char or varchar?
Which are the differences? and the better


Generally speaking, varchar or text() types are preferred. char() types
are padded. I.e. if you create a table with char(8) and insert 'abc' then
select it, you'll get 'abc ' back, i.e. abc followed by padding spaces
to make it 8 wide.

Most of the time this is not what the user wants.
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Nov 11 '05 #2

P: n/a
As of my knowlege, varchar as the choice when you have varying lenght
strings, because only the real string lenght is stored in the db, while
char is usefull when most of your records ar exactly the stringlenght
defined by the column, because no overhead is to be kept for storing the
actual stringlenght.

Regards

Edwin Quijada wrote:


Hoii!!

I am creating my struct and I have the question :
What I must use for character fields char or varchar?
Which are the differences? and the better
TIA

*-------------------------------------------------------*
*-Edwin Quijada
*-Developer DataBase
*-JQ Microsistemas
*-809-747-2787
* " Si deseas lograr cosas excepcionales debes de hacer cosas fuera de
lo comun"
*-------------------------------------------------------*

__________________________________________________ _______________
Charla con tus amigos en línea mediante MSN Messenger:
http://messenger.yupimsn.com/
---------------------------(end of broadcast)---------------------------
TIP 8: explain analyze is your friend

--
Andreas Fromm

-----------------------------
Drink wet cement...
... and get stoned


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Nov 11 '05 #3

P: n/a
On Wed, Sep 17, 2003 at 09:11:54AM +0200, Andreas Fromm wrote:
As of my knowlege, varchar as the choice when you have varying lenght
strings, because only the real string lenght is stored in the db, while
char is usefull when most of your records ar exactly the stringlenght
defined by the column, because no overhead is to be kept for storing the
actual stringlenght.


No, the overhead is present for char(n) as well, because it stores the
length in _bytes_ while the "n" is the length in characters; they could
be different.

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
One man's impedance mismatch is another man's layer of abstraction.
(Lincoln Yeoh)

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Nov 11 '05 #4

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