In the spirit of relieving the boredom that Marshall recently revealed,  I'm
going to let the frivolous side of me loose for a while,  and start some
threads that are just for fun.
But I'm going to try to limit myself, so that I won't displace messages that

I've been thinking about trees in the abstract lately, and
trying to classify them. I am not talking about trees as
a physical data structure, such as BTrees or Red-Black, but
rather trees as logical data structures. In other words,

article "We are the Web" by Kevin Kelly reads,
"A simple link, it turns out, is the most powerful invention of the
decade."

I hope  my post  won't offend people in this group,  as it's not my intention
to  annoy anyone or get someone do  my work for me.   I just  have nobody
else to ask for help :(
I'm studying informatics and I am to make a DB application.   I got a partner

I have seen many databases that tables with columns such as IsMale,IsFemale,
IsNull,Is...
All these were somekind of boolean type with yes/no or true/false or 1/0
values.In DBMSs that supports

Marshall,
This is an offshoot of the topic where you are exploring the comparison of
graph databases with systems of relations.
It's so tangential that I chose to start a new thread, rather than hijack

I am looking for a solution that hopefully someone here has tackled.  I want
to create "base" tables with fields that are intrinsic to the application.
I also want to allow the customers using the application to be able to
create their own fields so that they can easily customize ...

I found two definitions for 2NF:
1: A relation R(A,F) is in 2NF, when every attribute not belonging to
the primary key of R is fully functionally dependent on the primary key of R
2: A relation schema R is in 2NF if every nonprime attribute A in R is

I'm taking over an old DB and cannot decide if something which was done
in it is good or bad  :
A,B,C,D are tables linked together with foreign keys :
A->B->C->D

This discussion is triggerd by Jon Heggland's message about dimensional
units supported by user-defined type.
Mikito Harakiri wrote:

Does anyone have any insight or information on the origin
of the term "candidate key"? It seems like a standout bad
term in a field full of not-very-good terms.
A "candidate" is something that aspires to a particular position,

I'm an italian student of computer science and I'm trying to do an
implementation of nested intervals with continued fractions.

order to pass from an encoding (example Farey encoding) to materialized

How are issues of Null values handled when normalising a database?

    I have spent some time looking in this newsgroup to make sure this
has not been mentioned before and it seems like it has not.
    Most of the expressivity in SQL queries is required to build
complex reports. Common reporting tools like crystal reports break the

I'd like to suggest a new Normal Form definition, one that I'm calling Base
Normal Form, for lack of a better term.
The purpose is NOT to advance theory any further.  It's to make it easier to
teach introductory database design.