It appears as though you can define/select any number of tables and or
fields from different tables to define what makes up the fields within an
entity bean.
Cory
At 10:12 PM 11/7/00 +0100, Frank Eggink wrote:
>Hi Cory,
>
>How do they recognize relations between tables?
>
>Frank
>
>On Tuesday, November 07, 2000 3:32 PM, Cory Adams
[SMTP:[EMAIL PROTECTED]] wrote:
>> I just received JBuilder 4 Enterprise and I will say that it does an
>> amazing job at EJB so far. You can connect to a datasource via JDBC and
>> pick your tables and keys for Entity CMP. It's amazing.
>>
>> I'm still tweaking the deployment descriptors for Orion.
>>
>> Man the money you can save on Orion should go toward also purchasing JB4
>> Enterprise. The two together could be a very cutting edge solution.
>>
>> It does also have support for EJB 2.0 style descriptors.... Haven't tested
>> this yet though.
>>
>> Cory
>>
>>
>> At 09:37 AM 11/7/00 +0100, Frank Eggink wrote:
>> >I guess I'm using neither.
>> >
>> >The clue is that, when you stick to the rules, you have to write the
>> minimum one panel and one table
>> >per dataobject as all the access to the properties is done via methods and
>> each of those methods is
>> >specific for the dataobjects (e.g. getName(), setName(x)). When you have a
>> lot of dataobjects that is
>> >a bore.
>> >
>> >The 'pattern' I'm using abstracts away (= marketing speak) from the clean
>> OO model. The generator
>> >generates standard bean access (getProperty(index), setProperty(index, x)
>> and by using descriptors
>> >for the dataobjects and its relations is it possible to generate default
>> screens. Something you would
>> >most likely use reflection for when that was possible.
>> >
>> >Using reflection has two problems:
>> >- It does not work with Orion.
>> >- It works only on a per object basis.
>> >You could solve those by adding on the client side wrapper objects that
>> implement Just-Another-Layer.
>> >You can use reflection for that layer and if you device you object in a
>> clever way (using clever naming
>> >patterns) you -can- use reflection.
>> >
>> >Why the complex stuff and not generating the tables and the panel. Well,
>> in the system I'm using I plan
>> >to implement the option for users/systemmanager to tailor their screens.
>> You can do that when you
>> >generate screen on the fly, you can't when they are already compiled.
>> >
>> >It is a bit of an excercise but I am always strongly in favour to use as
>> less as possible code to build your
>> >final system. A lot of bugs stem from silly mistakes: the less code, the
>> less silly mistakes. And if in the
>> >above generator there is a silly mistake it is reproduced in a lot of
>> places: more chance to be discovered.
>> >
>> >
>> >I guess the same model could be used for dynamic creation of HTML.
>> >
>> >Frank
>> >
>> >On Monday, November 06, 2000 11:16 AM, Cory Adams
>> [SMTP:[EMAIL PROTECTED]] wrote:
>> >> Are you using the command or business object pattern?
>> >>
>> >> At 08:49 AM 11/6/00 +0100, Frank Eggink wrote:
>> >> >I'm using Swing instead of JSP.
>> >> >
>> >> >On Sunday, November 05, 2000 9:04 PM, Cory Adams
>> >> [SMTP:[EMAIL PROTECTED]] wrote:
>> >> >> Thanks for that update.
>> >> >>
>> >> >> Do you or does anyone else know of the MVC (model - view - control)
>> pattern
>> >> >> used with JSP - Servlets and EJB? I have read that a single servlet
>> >> >> becomes that controlling mechanism to the EJBs. I wondering how
that is
>> >> >> done?
>> >> >>
>> >> >> Cory
>> >> >>
>> >> >> At 10:23 PM 11/5/00 +0100, Frank Eggink wrote:
>> >> >> >My personal trade off was:
>> >> >> >
>> >> >> >Why not CMP 2.0 style:
>> >> >> >- Too scared to use it for real as it is not even officially
there ...
>> >> >> >
>> >> >> >Why choose for CMP 1.1?
>> >> >> >- CMP is more portable (across db's).
>> >> >> >- Working already towards EJB2.0.
>> >> >> >- The claim is CMP can be optimized better (I would be happy to know
>> more
>> >> >> details about that, until that time it is a bit
>> >> >> >of a bet on a blackhorse for me).
>> >> >> >
>> >> >> >Why choose for BMP?
>> >> >> >- I do not know yet whether I'll run into trouble with complex and
>> highly
>> >> >> flexible queries requirements
>> >> >> >for Query By Example forms. The requirement for extra flexibility
could
>> >> >> become an argument.
>> >> >> >
>> >> >> >I would say if you can spend the time learning enough about CMP
1.1 I
>> >> >> would go for that as a first option. The EJB1.1
>> >> >> >specs are even written so that you can sub class a CMP bean to
create a
>> >> >> BMP bean.
>> >> >> >
>> >> >> >
>> >> >> >One of the biggest disadavantages of EJB's is the tremendous
amount of
>> >> >> redundant code you have to write. Add for
>> >> >> >instance a field to a bean. You'll have to change three files
>> minimum and
>> >> >> don't make mistakes as that will cost you time.
>> >> >> >This disadavantage applies to both CMP and BMP and will apply to
>> EJB2.0 as
>> >> >> well.
>> >> >> >
>> >> >> >
>> >> >> >What I'm doing is using EJB1.1 CMP and generate beans and stuff
using a
>> >> >> slightly more advanced bean
>> >> >> >generator then the standard ones. Based on a datamodel
>> (Entity-Relation)
>> >> >> it generates a set of beans for
>> >> >> >your application (including the remote and home interfaces and the
>> *.xml
>> >> >> files of course). The generated
>> >> >> >beans include the fields, the finder queries, the additional
methods to
>> >> >> retrieve related beans etc.
>> >> >> >
>> >> >> >As an additional bonus the beans include a more abstract way to
>> access the
>> >> >> properties (myBean.getProperty(int index))
>> >> >> >as the client side of orion does not allow reflection. I use that to
>> >> >> generate forms and tables on the client.
>> >> >> >
>> >> >> >The generator adds a tremendous flexibility (I can switch to BMP /
>> EJB2.0
>> >> >> easily), makes CMP 1.1 managable and
>> >> >> >keeps me away from EJB2.0 while it is still too early for me. For
the
>> >> >> rest: Im a notoruios mifftyper and am able to
>> >> >> >spend tons of time debug typos in 2638 lines of very closely
resembling
>> >> >> code. That problem is solved as well :-)
>> >> >> >
>> >> >> >
>> >> >> >Frank
>> >> >> >
>> >> >> >On Saturday, November 04, 2000 12:10 AM, Cory Adams
>> >> >> [SMTP:[EMAIL PROTECTED]] wrote:
>> >> >> >> At 11:44 PM 11/3/00 +0100, Robert Krueger wrote:
>> >> >> >> >At 11:23 03.11.00 , you wrote:
>> >> >> >> >>I have looked through the 2.0 spec and find the chapters
regarding
>> >> CMP to
>> >> >> >> >>be daunting. It appears as though the complexity of writing
my own
>> >> >> SQL in
>> >> >> >> >>BMP has to be balanced against learning an entire new way of
>> managin
>> >> >> >> >>persistence within the XML deployment descriptors which seems to
>> be no
>> >> >> less
>> >> >> >> >>or perhaps even more complicated than BMP????
>> >> >> >> >>
>> >> >> >> >>Or am I missing something with regard to CMP being easier?
>> >> >> >> >
>> >> >> >> >yes, two things:
>> >> >> >> >
>> >> >> >> >1. your code including the queries is guaranteed to be portable
>> between
>> >> >> ejb
>> >> >> >> >servers and databases (that's the theory)
>> >> >> >> >2. you cannot possibly make optimizations using BMP that the
>> container
>> >> >> can
>> >> >> >> >make using CMP
>> >> >> >> >
>> >> >> >> >why do you have to use ejb2.0 CMP? you didn't mention 1.1 cmp
as an
>> >> >> >> >alternative?
>> >> >> >> >
>> >> >> >>
>> >> >> >> Hmmm..... I can find even less regarding 1.1 CMP. I have the
>> >> ORielly book
>> >> >> >> as well as the Mastering EJB books. The 2.0 spec is what I'm
using
>> >> because
>> >> >> >> I would think (perhaps wrongly) that EJB 2.0 would maybe be easier
>> >> and or
>> >> >> >> offer more functionality??? Chapters 9 and 10 are over 100 pages
>> which
>> >> >> >> have to do with CMP. The last thing I need to do is learn another
>> query
>> >> >> >> language which is what some of the 2.0 spec seemed to indicate I
>> >> would need
>> >> >> >> to do....
>> >> >> >>
>> >> >> >> I also understand points 1 and 2 above but they do not address my
>> >> original
>> >> >> >> question of the relative complexity between BMP and CMP.
Basically 1
>> >> and 2
>> >> >> >> are irrelevant to me if I can not implement CMP and can not
>> practically
>> >> >> >> compare the relative complexity between the two because I just
don't
>> >> >> >> understand CMP so I will keep digging through examples and utilize
>> >> the post
>> >> >> >> that has been helpful that somebody posted earlier today :
>> >> >> >> http://www.execpc.com/~gopalan/java/entity.html .
>> >> >> >>
>> >> >> >> Thanks,
>> >> >> >>
>> >> >> >> Cory
>> >> >> >>
>> >> >> >>
>> >> >> >> >regards,
>> >> >> >> >
>> >> >> >> >robert
>> >> >> >> >
>> >> >> >> >>Thanks,
>> >> >> >> >>
>> >> >> >> >>Cory
>> >> >> >> >
>> >> >> >> >(-) Robert Kruger
>> >> >> >> >(-) SIGNAL 7 Gesellschaft fur Informationstechnologie mbH
>> >> >> >> >(-) Bruder-Knau?-Str. 79 - 64285 Darmstadt,
>> >> >> >> >(-) Tel: 06151 665401, Fax: 06151 665373
>> >> >> >> >(-) [EMAIL PROTECTED], www.signal7.de
>> >> >> >> >
>> >> >> >> >
>> >> >> >> >
>> >> >> >>
>> >> >> >
>> >> >> >
>> >> >>
>> >> >
>> >> >
>> >>
>> >
>> >
>>
>
>
