[Year 12 IT Apps] ITA U3O2 key knowledge 9

[Mark KELLY]

Hi all.  Welcome back to work.

1.  Need a bit of help reading a database KK dotpoint - "data formats,
including limited length, unlimited length, *incremental* (text); integer,
auto string number, long (number); date, 24-hour clock (date/time); dollar
(currency); true and false (representation of Boolean logic)"

I have not come across 'incremental' text fields before.  Googling suggests
it might perhaps be referring to the auto-entry of incrementing serial
numbers into a field?

And later it refers to 'auto string number' - is this an auto-entered
numeric serial number?  In which case, what does 'auto *string* number'
mean?

N.B. the term '*incremental' *did not appear in the draft study design.
Also, the mysterious 'auto string number' did not appear: instead there was
the clearer 'auto incremented number'... is that what the accredited SD
meant to say?

Any suggestions, anyone?

--------------

2. While I'm on this KK, I'm wondering about the usage of the term 'data
format'.  I've believed data format refers to the way data is
*presented*(e.g. a date could be shown as text or in a calendar
control; numbers can be
formatted with different number of decimal places, thousands separators,
right justified etc).

But KK9 refers to things like integer and long as being data formats rather
than data types, which I'd call them since they define the storage needs of
the data rather the way it is formatted in output.  Much the same applies to
limited & unlimited length text fields: they do not differ in appearance,
they are fundamentally different types of storage entities.

And date and time are listed as formats of date/time.  Again, I would argue
that they are distinctly different field types rather than display
variants.  In Filemaker, my primary RDBMS tool, there are different field
types for date, time and timestamp (a combination of date and time in one
container). Of course dates and times can be formatted in various ways in
output, but they are not stored the same...

I am happy with the other data formats mentioned in KK9 such as currency
being a special format for numbers, but in the previous dotpoint currency is
also mandated as a data *type*.  This may be because Access confuses things
by having both a currency *format* and a currency *datatype*) - I'm looking
at looking at
http://www.everythingaccess.com/tutorials.asp?ID=Using-the-Currency-field-data-type---without-the-hassle.
Filemaker does not have a currency data type... do other RDBMS?  I hope this
is not another case of Access parochialism.

I think we need to be rather careful distinguishing between field
*types*(U3O2KK8) and field
*formats* (U3O2KK9).


-- 
Mark Kelly
Manager - Information Systems
McKinnon Secondary College
McKinnon Rd McKinnon 3204, Victoria, Australia
Direct line / Voicemail: 8520 9085
School Phone +613 8520 9000
School Fax +613 9578 9253
kel at mckinnonsc.vic.edu.au

Webmaster - http://www.mckinnonsc.vic.edu.au
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