Re: How to avoid database deadlocks?

[Johan Eltes]

Hi Janne!

What is your rational for using BMT, You rarely see BMT being used
those days. BMT, as you and others of this thread has pointed out, adds
its own set of mechanics you will need to fight (at least in the case
of searching for data).
/Johan

2003-11-24 kl. 15.00 skrev Janne Mattila:

Your case would be simple if it were read only. However, it's not
      and that makes it complex. This isn't unique to EJB or solved
      magically by EJB or any other
technology (with the possible exception of some AI driven design
      tool). This is basic concurrency and a classic case of deadlock
as
      explained in any introductory text
on database design.
      If this is a complex case, I am really interested in seeing a
simple
      case. Two views - one shows cd and related artist and the other
shows
      artist and related cd's. How is this complex? And this _is_
unique to
      EJB. There would not be any updates to the database unless EJBs
were
      used. Using EJBs is the cause why ejbStore() gets called at the
end
      of transaction even when no updates have been made.
As I said above, EJBs don't remove the worry of transactions. They
      offer declarative transactions. That may not seem like much with
a
      single database in an non
clustered server. Add multiple data sources and clustering and it's
      quite a lot of complexity hidden behind the bean interface.

      You were not talking about declarative transactions, but
demarcating
      transactions manually with JTA. You don't need EJB's for that.
If you
      end up writing transactions yourselfs with JTA, why use EJB's
with
      the added complexity when you could just use JTA separately.
      Clustering? That is not part of EJB specification.
Programming is all about trade offs. Following patterns blindly is
      never
a good idea.
I agree. What was the part where I was following patterns blindly?
By assuming that a session facade with one overall transaction was
      the only useful pattern.

      Oh come on. How is the example I mentioned not suitable for
session
      facade pattern? If that is not, then what is? Have you suggested
a
      better alternative? Or do you just like preaching?
=======================================================================
====
To unsubscribe, send email to [EMAIL PROTECTED] and include in the
body
of the message "signoff EJB-INTEREST".  For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST".  For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".