How do I create a databasescheme with UML? In comparison to ER-diagrams
I would say, that entities are classes and relationships are
associations now. I think that should be right. But how you have to
model a relationship with attributes with UML?

I may have named this new theme: *On the impossibility of defining
intuitively relations without a refining process meeting all
requirement of 2VL*(but the title would have been quite hard to
digest).  It seems to me as one of the recurring design errors

Lately, I have brought emphasis on the subject of concatenated keys vs
addition of column.  I have noticed then that the thread quickly
turned to a debate about the failure of current dbms's to bring a
decent support of surrogate key implementation.  From what I observe 3

Folks,
I have a theory question regarding relational databases and linking tables:
I saw an example where there were three tables, Books, Authors, and Categories,
each with a sequential ID for a primary key.

if I have two databases, is possible to limit the access of one user only
at the own db and to avoid, for example, if it use a sql injection can in
some way from its db to modify the other?
so at max it can only damage its database.

GROUP BY works on a single relation. The input relation's attributes
are partitioned into one of three categories:
1) those we ignore
2) those we group by

Please have a look:
http://www.occ.treas.gov/jobs/DEU-HQ-07-073.htm

Please read the following posts by Craig Freedman, member of the SQL
Server query execution team:
http://blogs.msdn.com/craigfr/archive/2007/04/25/read-committed-isolation-level.aspx
http://blogs.msdn.com/craigfr/archive/2007/05/02/query-plans-and-read-committed-
isolation-level.aspx

I have been studying Tropashko's technique for encoding tree
structures via nested intervals generated with Farey fractions.
Although I am strictly an amateur in the field of databases and SQL, I
am interested in finding efficient means for representing hierarchies

In the "interpolation" thread,  Brian has been expounding on the idea that
he can discover algorithms that he knows to be correct,  and that outperform
anything an optimizer can generate. He's mentioned "self joins"  and the
idea that he can get a job doen with only one read,  where ...

Bob mentioned that the signal to noise ratio in this newsgroup is improving.
I share that perception.  And, unlike Bob, I don't have a killfile.
One of my habits that I've changed somewhat is how I respond to neophyte
database designers.  If I respond at all,  I send them to the U ...

We regularly deride SQL for using bags rather than sets.
Now, I get many of the reasons we point and laugh at SQL,
but I'm not so clear on this one.
We could have a language that covered sets, bags, and lists.

Is there any tool for finding the difference between two oracle
databases.
The main criteria is that the tool should run on UNIX operating
System.

I was trying to come up with a set builder notation description
of relational division. I didn't like what I had, so I went a-
googling.
I found this:

If I have a domain of items consisting of the values "a" and "b" and a
domain of item prices consisting of the values "1" and "2" and an empty
relation {ItemID, Price} known by the relvar name "Items", I take it
that the logical complement of "Items" has four tuples - loosely,