Re: Nearest Common Ancestor Report (XDb1's $1000 Challenge)

On Thu, 20 May 2004 19:39:18 -0300, Leandro Guimaraens Faria Corsetti Dutra wrote:

>Em Thu, 20 May 2004 23:38:58 +0200, Hugo Kornelis escreveu:
>
>> On 19 May 2004 20:03:18 -0700, Neo wrote:
>>
>> (snip class/domain stuff)
>>>> a datatype as a superset of many domains.
>
> Where did this come from?
>
> AFAIK a data type is the domain, plus operators.
>
>
>>>Suppose, car is the class of car1. Car1 has the attribute color. The
>>>attribute's value can be from the domain containing red and green.
>>>Would data type be red, green and blue (assume these are all the
>>>colors)?
>>
>> No. The data type would be character.
>
> Are you thinking SQL? AFAIU it would be {red, green} plus
>applicable operators.

Hi Leandro,

Yes, I am thinking SQL. As I already mentioned elsewhere in this thread, I'm not a theorist.

My daily job involves datamodelling and building applications with MS SQL Server at the core. In modelling, I use the term "domein" (which is the literal Dutch translation of domain - but this might be a situation where the literal translation is wrong) for a set of valid values. When I start creating tables, SQL Server wants me to supply a "data_type" for each column.

I never think of a data type as something that includes operators. I do check the data type before choosing an operator.

Like I said - I'm not a theorist.

Best, Hugo

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