[AccessD] Very interesting quirk in table design...

On 14 May 2003 at 8:30, Henry Simpson wrote:

> Curious that in Access 97, and I'll assume subsequent versions as
> well, a yes/no field stores 2 bytes for each entry.  Using a numeric
> value like a byte requires half the storage and gives you 8 states
> that equate to 8 two state fields or 4 four state fields or whatever
> other combination of 8 bits you devise, plus null.  I've never
> understood why the yes/no field requires two bytes and use bytes for
> boolean fields for the increased flexibility.  Form logic doesn't seem
> to require any change if you simply use one byte field for each field
> requiring a boolean display.
> 

It's for speed/simplicity versus storage requirements.

A 32 bit (long) data type is the quickest and easiest to 
retrieve/mainipuate/store in a 32 bit OS.

If you used a single bit to store a yes/no field, it would reduce the 
storage requirement, but think about how you would then have to 
store/locate/ index etc that particualr bit. It would make it a very 
slow datatype to use in comparison.

If you only have a single Yes/No field in the table, what are you 
going to do with the other 7 bits in the byte anyway - so you might 
as well just store it as a whole byte. Once you take that step, you 
might as well use a long for speed rather than a byte (You don't use 
single byte Integer variables do you <g>)







-- 
Lexacorp Ltd
http://www.lexacorp.com.pg
Information Technology Consultancy, Software Development,System 
Support.