How to realize "INNER JOIN" analog

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EJB programming & troubleshooting: How to realize "INNER JOIN" analog

  1. How to realize "INNER JOIN" analog (7 messages)

    Hi!
    We're just "lammers" in EJB Design&Implementation although we have a profound experience in OOP.

    The questions are the following. There're 2 entity beans each connected to a single table in database. How to:

    - implement "INNER JOIN" SQL-statement on these tables through beans;
    - implement "UNION" SQL-statement on these tables

    P.S. We use EJB 1.1 spec., Borland AppServer 4.5 and JBuilder7.

    P.P.S. We'd be very graceful for any link to resouces regarding configuring AppServer (JNDI-tree on several computers). And...

    What AppServer is to be most convenient to configure, to use etc...

    Threaded Messages (7)

  2. I think this can be better resolved if you create the views first in the database then have your entity beans use the views.

    "What AppServer is to be most convenient to configure, to use etc..." -- Well, what can I say? Of course, WEBLOGIC!

    Regards,

    Marco
  3. How to realize "INNER JOIN" analog[ Go to top ]

    If u r using BMP Entity bean, everything is in your control ofcourse, u can write you sql statements as u wish.

    I suppose you are using CMP Entity Beans.

    Views is the most obvious way to solve it. That's a good suggestion.In this case since there is only one table it is likely to work.

    But this may not resolve many problems. For example several databases will prevent you from updating or inserting to multiple tables if the view is using multiple tables.
    CMP Entity Beans are so hopeless !
  4. How to realize "INNER JOIN" analog[ Go to top ]

    Don't say anything bad against a technology you haven't used. I mean, have not really really used. There are many advantages to CMPs. And of course, I'm not taking it out from what you said, there are also disadvantages. But each technology were made for specific reasons. And for each reason, you can have several choices (and that's the beauty of it). It's up to you to choose. I use CMPs in my project, but I also used JDOs and BMPs.

    And besides, no one is forcing you to use CMPs. So don't say they're hopeless.

    Peace!

    Marco
  5. How to realize "INNER JOIN" analog[ Go to top ]

    There are so many people who hears something about something and even though they really have not proven it, say it to others as if they really really know it. In these discussions, before I say something, especially with coding, I code it myself first and see if what I'm gonna say will really work. If it does not, I keep silent.
  6. How to realize "INNER JOIN" analog[ Go to top ]

    Marco, my dearest friend, that was just a general comment on the state of things in j2ee world. With the advent of jdo, many have started wondering about the future of entity beans themselves etc.

    But, thanks for your comments. :) I have used entity beans, and have not been convinced of there usefulness much. But that does not mean no one else finds them useful. That's just my opinion.
  7. How to realize "INNER JOIN" analog[ Go to top ]

    Good we got it cleared! I don't wanna have any misunderstanding with anyone here... I know this forums for everyone to help everyone...

    Regards,

    Marco
  8. How to realize "INNER JOIN" analog[ Go to top ]

    Marco, my dearest friend, that was just a general comment on the state of things in j2ee world. With the advent of jdo, many have started wondering about the future of entity beans themselves etc.

    But, thanks for your comments. :) I have used entity beans, and have not been convinced of there usefulness much. But that does not mean no one else finds them useful. That's just my opinion.