choice of field types and performance

2002-07-09 Thread Marko Djukic

what is generally better to use:
- one field of type 'set' (eg.: 'apples','cherries','pears','bananas')
- or multiple fields of type true/false for each value above?

just to make sure, mysql doesn't store each value selected in the set in each record? 
or does it?

thanks,

marko

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Re: choice of field types and performance

2002-07-09 Thread Roger Baklund

* Marko Djukic
 what is generally better to use:
 - one field of type 'set' (eg.: 'apples','cherries','pears','bananas')
 - or multiple fields of type true/false for each value above?

Field type SET, because the field types BIT and BOOL are 'fake' (synonyms
for TINYINT), occupying a full byte for each field.

 just to make sure, mysql doesn't store each value selected in the
 set in each record? or does it?

No, only one bit is used for each value in the SET (minimum 8 bits/row,
maximum 64).

URL: http://www.mysql.com/doc/S/E/SET.html 

--
Roger


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