Re: The Practical Benefits of the Relational Model

Paul Vernon wrote:

> "Leandro Guimarães Faria Corsetti Dutra" wrote in message
> news:aq5vc9$6trji$2_at_ID-148886.news.dfncis.de...
>

>>> If so, how do you propose to 'make known to both system and other
>>>  users' such constraints?
>> 
>> Still waiting for the second part of the article!

        Yes, I could. It's at home, I do Usenet at work. Will try to remember at lunch time.

>> But seriously, the best approximation I know of are the domain,
>> column, relation and database constraints.

        The whole point is that the name is not meaningful to the system, and only meaningful to the user in a context, or if explained by documentation perhaps.

        About the type, it is just the domain and attribute constraints, QED.

> I.e. you cannot insert a proposition into a database if there is not
> a matching relvar to 'receive it (and,of course it does break any of
> the 'other' constraints mentioned)

        Obviously.

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