The script below models the following requirements using an
experimental db (XDb3). The equivalent can be performed with an RMDB
using nested relations and generic modelling.
- A person has 0 to may diaries.

if we create our own rdb what can be the different methods of storing
the data.
if we store in file then do we use a single file or diffrent file for
each tables,db.

Hi, I need some help with this database question..
suppose s(R) = {A, B, C, D}
and suppose FDs
A,B->C; C->D; D->A

I have a table which represents a tree of forums using nested sets.
Here are the fields: id, root_id, left, right, level, label.
I have a string which is like a path.
For example, Forum/Sub-forum/Sub-sub-forum

/*
This example is simplified and distilled down from my real
problem. I believe it to be representative. A person
owning a vehicle is represented by joining the

I'll try this another way (persistence is my middle name?).  I use a precise
definition of "relation" from mathematics.  It is in the glossary mAsterdam
collected that I sent out a few days ago.  However, it seems that most folks
here use some other definition(s) of the term.  ...

We are experiencing a deadlock issue using MS SQL 2000 that's
generating some debate in our office.  We have two stored procedures
SP1 and SP2 running in the same transaction along with couple other
stored procedures, SP1 does a deletion on one table, then later SP2

I'm learning database design and have a slight problem with a relationship
I'm trying to model.
To be specific, I'm working on the example of a bookshop that sells rare and
out-of-print books. Each book is tracked as a unique object, and so can be

This is the most recent glossary I found.  As you can see, it is a work in
progress.  Until we can entice mAsterdam back, I'm willing to be a trustee
of this document unless there is someone else who will volunteer.  I'm
sending the following unchanged.  I am particulary ...

The top of this posting is intended to be devoid of opinions, so please
correct if I have any misconceptions prior to the question.
1) SQL-DBMS's (at least those that conform to SQL92) provide no constraints
on the user creating new tables to restrict base tables from being

NFNF, NF2, or NF^2 = Non-First-Normal-Form is how products such as IBM U2
databases describe themselves
ftp://ftp.software.ibm.com/software/data/u2/pubs/whitepapers/nested_rdbms.pdf
Some NF2 products are also called MultiValue or PICK(-like) and include:

Hello again,
It has been suggested in this newsgroup that relation-valued attributes
are unnecessary because anything that can be represented with a
relation with RVAs can also be represented using an equivalent

I was playing with doing som stats in SQL, and I need some feedback.
What should you do with NULLs in a computation of Pearson's r?  Let me
do a "cut & paste" of the definition of r and some SQL code at the
bottom of this posting.

The subject say it all.
I would like to buy a good book on Data modeling I know how to make
conceptual model, physic model, ERX (?) and all this.
What I would like to get better at is to know how to enforce

Hi, I have this model:
DEPARTMENTS    (dp_id, cl_id, dp_otherStuff)
CLIENT        (cl_id, cl_otherStuff)
CONTRACT    (cn_id, cn_details)