i'm the author of a simple open-source database engine. i'm currently
adding recovery/logging, and i have some practical questions about the
implementation.
I have 3 options.

A user enters a date range (ie. 2 dates, '2008-04-01' and
'2008-04-03'), the problem is to determine how many open events exist
on each day in this interval.
Assume that the "events" table has a "start_date" and an "end_date".

Hello guys, this one is for one of my assignments. I want explanations
and hints only.
I'm still confused with the concepts of candidate keys and primary
key. We have a patient medication form from an hospital with these:

am doing a project on hash join. implementation to be done on hasNext
and getNext interface.
hash join has 2 phases. partitioning phase and probing phase.
but i dont understand where the partition will be done. in hasNext or

How does one model behavior?
It would seem to me that, since conveying behavior from one object to
another rests on messages,  and since messages are made of data,  that one
needs a data model for the messaging system before one begins to come up

beginner in ER.. Need more practical works and scenarios please help.
Thanks

How is behavior specified?
In particular, is the specification expressed as declaratives or as
imperatives?

In the early days of the relational model, the words *intention* and
"extension* were used respectively to mean *query* and *response*.
That is, an SQL (or other database language) query represented your
*intention*, that which defined what you wanted to retrieve. What the

RDBMSes are sometimes described as a reaction against network-/
hierarchical databases. I believe that I've read that CODASYL-like DBMSes
resulted in databases which were very hard to maintain.
Does someone know of more concrete descriptions of what problems the old

On Mar 3, 2:07 pm, Thomas Gagne <tga...@wide-open-west.com> wrote:

My ISP just changed USENET service providers.  I have seen no new
posts since for this newsgroup.  If you see no replies to this
message, please post one so I know that I can send to and receive
from.

I am new to the field so I apologize if this question seems trivial. I am
currently working on distributed software transactional memory (STM). Since
database transactions are the semantic inspiration for STM, I was wondering
about the level of concurrency of distributed database ...