Paul wrote:
> Bernard Peek wrote:
>
>>>I don't understand this point at all. To me it seems almost a tautology
>>>that databases are models of reality (unless of course they're modelling
>>>some virtual world that doesn't exist outside the database).
>>
>>The metadata in the database is a model of reality, and datamodelling
>>concerns itself with metadata.
>
> Hmm maybe it comes down to semantics then, because the way I look at it,
> the metadata describes a top-level model of reality, and the data just
> provides a more detailed model of reality.
>
> For example, consider a group of employees I want to model. For
> simplicity assume I'm using a single table.
>
> The metadata that descibes that table gives me a very broad model of
> reality: it tells me that I'm dealing with a group of people who have
> certain attributes.
>
> But it doesn't tell me who those people are or what values the
> attributes have for each person - for that I have to supply the row
> data. But to me that's still a model; it's just more detailed, giving me
> the names, departments etc. for each person. Each row is a model of a
> person, if you like.
>
> Maybe I'm belabouring an unimportant point though and it just comes down
> to the definition of the word "model" in different contexts.
>
> I agree that what we commonly refer to as "data modelling" is all about
> metadata, but I still think data itself is also about modelling.
To the user of the data, yes, a model (if the database is any good).
To the DBMS it's meaningless signs to be cleverly kept - no model.
Received on Sun May 08 2005 - 04:44:10 CDT
