Re: Database design

x schrieb:
> "Alexandr Savinov" <spam_at_conceptoriented.com> wrote in message
> news:43fc2df6$1_at_news.fhg.de...
>

>>> This whole 'flat' debate is nonsense too. Write a database down in its
>>> mathematical form, devoid of tables, and tell me how on earth it can be
>>> flat (which semantically means two-dimensional of course), deep, fat,
>>> thin, whatever. If you mean it doesn't support composite types say
>>> that. If you mean it contains no explicit links, say that. Calling it
>>> flat is semantically redundant and doesn't aid any real discussion.

>> I have seen at least two definitions of the term "flat" in this

>> - a structure is said to be flat if it consists of columns and rows,
>> that is, any element can be retrieved by specifying a column and a row.

>> - a structure is said to be flat if it is equivalent to n-dimensional
>> space (that is, with only one level where points are characterized by
>> their coordinates along n dimensions).

>> It is an answer on your question "how on earth it can be flat".

>> You can also define a structure as deep. For example, if it is
>> equivalent to a hierarchical space. It is also not excluded that some
>> other term could be helpful such as fat, thin etc. Notice that these
>> terms are far from the most exotic ones in science. (Fuzziness and
>> roughness of sets, charmness of quarks etc.)

There is several reasons why it is useful:

1. It allows us to get an informal impression and what is the essence, what we are talking about. An informal characterization (an idea) is the primary thing while formalities is the secondary thing (a tool which makes it easier to derive consequences).
2. Just because we use other informal terms in order to describe a theory or approach. Eventually, in any academic paper and in this group most of words have no formal definition. And this does not prevent us to comprehend them. And again: writing formulas does not add a value to any theory - it is only a form which may make it easer or more difficult to understand.
3. This group is intended to discuss what is not covered by academic papers so there is nothing bad that we can introduce something unusual.

Anyway, I do not understand why a structure without an order (hierarchy, multiple levels, depth etc.) cannot be characterized as flat? It is rather precise characterization (in contrast to many terms from academic papers which are frequently simply misleading).

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