Re: trees, trees, trees
Date: Mon, 25 Jun 2012 01:46:58 +0200
Message-ID: <js88v9$d4s$1_at_news.task.gda.pl>
Peter Schneider wrote:
> I strongly disagree. Each table in a relational database has to have at
> least a primary key [...]
> [...]If you haven't thought yet about such kind of questions, my guess is
> that you probably haven't thought deep enough about the entities in real
> life that your DB is trying to model.
you said many interesting things of which no one makes it closer to solve the problem. and it's not the point of my post either.
imagine there is a table, that you're not an owner, that you're not designer, that you don't even intend to model anything etc. you're just a guy who likes solving puzzles. you were given this table. it has some structure. it's a good structure, it has some business meaning for someone (remember: you're not designer). and imagine that there is a quite a prize for just solving the puzzle. not for asking questions and bringing up other interesting, but unrelated subjects (they give minus points for this and call IRS).
so, can you solve the problem with pure SQL? if there is anything that needs to be explained about the problem please ask, I will explain in more datails. but I think that the data set I presented along with the expected results are self-explanatory.
thank you,
geos
Received on Sun Jun 24 2012 - 18:46:58 CDT