[Year 12 IT Apps] The sample ITA questions -- Number 3in Section B

[Mark KELLY]

Sadly, while in a perfect world Boolean is stored as one bit, apparently it
doesn't happen that way: according to discussion at
http://www.access-programmers.co.uk/forums/showthread.php?t=152490 Boolean
in Access is stored (like Filemaker does) as an integer: 2 entire bytes!

So it seems that the space-saving glory of Boolean is a bit of false
advertising...

On 5 April 2011 20:14, Timmer-Arends <timmer at melbpc.org.au> wrote:

>  Hello Mark K and Matt
>
> 1. So Access doesn't have a true Boolean datatype.... and neither does
> Filemaker (one uses a number field with values of non-zero or 0). Which
> RDBMS *does* have a fair dinkum native Boolean datatype?
>
> Access does have a "fair dinkum" Boolean data type - it's a 1 bit field and
> that means it can be either 0 or 1 and you can't get much more Boolean than
> that. Null is not allowed. As the setter-upper of the db you can choose a
> number of ways to display it, the default being yes/no.
> 2. I always thought Boolean operators were:
> NOT
> OR
> AND
> Thus in the sample paper M / F the Boolean operator would OR?
>
> But the question doesn't ask about operator (or have I missed something?).
> It asks about data type and I agree with other comments: F/M is the only
> possible answer because it's a two value field, but I wouldn't have thought
> it would be a good idea for a number of reasons including every time you
> want to display it you have to do an IF operation
> (IF(gender,"Female","Male") or something), also, in Access at least, NULL
> would not be allowed and I can think of circumstances where this would a be
> valid entry (for example, maybe we just don't know, in which case NULL would
> be more valid than a forced True or False)
>
>
>
> _______________________________________________
> http://www.edulists.com.au - FAQ, resources, subscribe, unsubscribe
> IT Applications Mailing List kindly supported by
> http://www.vcaa.vic.edu.au/vce/studies/infotech/itapplications3-4.html -
> Victorian Curriculum and Assessment Authority and
> http://www.vitta.org.au  - VITTA Victorian Information Technology Teachers
> Association Inc
>



-- 
Mark Kelly
Manager of ICT, Reporting, IT Learning Area
McKinnon Secondary College
McKinnon Rd McKinnon 3204, Victoria, Australia
Direct line / Voicemail: +613 8520 9085, Fax +613 9578 9253
kel at mckinnonsc.vic.edu.au
VCE IT Lecture Notes: http://vceit.com
Moderator: IT Applications Edulist

All generalisations are false, except this one.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.edulists.com.au/pipermail/itapps/attachments/20110406/a4baed59/attachment-0001.html