Re: Life cycle of beans(Session and entity)

[Murthy, A (CAP, GEFA, Contractor)]

Hi everyone,
I don't know know whether it is a silly question, but I want to know the
answer for the following questions.

I have a doubt. How can we insert a row in database using Entity Beans?
First of all, Suppose  I have a primary key having ,say, 100 coulmns. and
suppose my table has 100 more columns which are not part of the primary key.

So in that case, first I have to create a primary key class with the 100
columns as primary key. is it?
Now my question is, when I call the create method, I need to pass these 100
columns to the Create method. then How the bean is going to insert a row
into the database?
And also, how do we need to manage the entity beans if I have a composite
primary key, suppose if I need to join 5 tables then how to do that and
insert or update the tables?

Please explain me  this situation? In this case, which persistence mechanism
do i need to use? is it CMP or BMP?

I hope every one understood my question.

Murthy A Suryanarayana
mailto  : [EMAIL PROTECTED]



-----Original Message-----
From: Sonia [mailto:[EMAIL PROTECTED]]
Sent: Thursday, August 17, 2000 2:14 AM
To: [EMAIL PROTECTED]
Subject: Re: Life cycle of beans(Session and entity)


You can create a Bean with a class as primary key, in that class you can put
as many attributes as you want, be careful with the names, the name of the
attribute must be the same in the class and in the bean.

In the Deployment you have to say that the primary key is a class

Bye

            Sonia
----- Original Message -----
From: Murthy, A (CAP, GEFA, Contractor) <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, August 16, 2000 11:22 PM
Subject: Re: Life cycle of beans(Session and entity)


> How do we create or design entity beans if the tables have composite
primary
> keys?
>
> Murthy A Suryanarayana
> GE Financial Assurance
> LTC - OPS2000 Project
> ------------------------------------------------------------------------
> -------------------
> Day     : (415) 492 7834
> Dial-Com        :  8 *    277 7834
> Fax     : (415) 492 7699
> mailto  : [EMAIL PROTECTED]
>
>
>
> -----Original Message-----
> From: Dave Wolf [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, August 16, 2000 2:07 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Life cycle of beans(Session and entity)
>
>
> Failover of stateful EJB's is a feature of some servers not of the code
you
> write or of EJB itself.  Sybase EAServer can manage failover of stateful
> Session beans and will automatically recover the in-memory state of the
> bean.  However this is generally a container feature rather then a
> developer's work.
>
> Dave Wolf
> Internet Applications Division
> Sybase
>
>
> > -----Original Message-----
> > From: A mailing list for Enterprise JavaBeans development
> > [mailto:[EMAIL PROTECTED]]On Behalf Of Murthy, A (CAP, GEFA,
> > Contractor)
> > Sent: Wednesday, August 16, 2000 4:20 PM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Life cycle of beans(Session and entity)
> >
> >
> > Hi,
> > Suppose I have a stateful session bean.  USer is logged into the
> > aplication
> > and doing his work. Suppose, in between application server crashed or
> > shutdown. In that case, if we restart the server, can I restore or load
my
> > previous state of my stateful session bean before server crash /
shutdown
> > back after the server restarted again ? Can we store the state in
> > the disk?
> >
> > Murthy A Suryanarayana
> > GE Financial Assurance
> > LTC - OPS2000 Project
> > ------------------------------------------------------------------------
> > -------------------
> > Day     : (415) 492 7834
> > Dial-Com        :  8 *    277 7834
> > Fax     : (415) 492 7699
> > mailto  : [EMAIL PROTECTED]
> >
> >
> >
> > -----Original Message-----
> > From: Vivek Singh [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, August 16, 2000 3:35 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Life cycle of beans(Session and entity)
> >
> >
> > what u say seems quite logical to me....but the says otherwise
> > e.g. Ed Roman
> > matering EJB.
> > I can copy and paste as these things r diabled in the book.
> >
> > another question:
> > Can we have stateless session bean having ejbCreate method with
> > arguments....
> >
> > If we can do that then we can manage session on our own....i am stating
a
> > probability where ejbCreate() method of stateless session bean need to
be
> > called everytime...
> >
> > Can someone clarify the confusion....
> >
> > Thanks
> >
> > Vivek
> >
> > -----Original Message-----
> > From: Rajesh Balu [mailto:[EMAIL PROTECTED]]
> > Sent: Friday, June 02, 2000 1:19 PM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Life cycle of beans(Session and entity)
> >
> >
> > While it is true that create() and ejbCreate() methods for a
> > stateless bean
> > cannot take any parameters, but when a client calls create() method on a
> > stateless bean, ejbCreate() is not called on the bean instance.
> > When an EJB
> > server starts up, it creates a certain amount of stateless bean
instances,
> > calls the ejbCreate() method for each of them and stores them in the poo
l.
> > Subsequently, when a client invokes create() method on the home,
> > the server
> > simply picks up an instance randomly and associates it to the EJBObject.
> > This
> > is significantly different from Entity and Stateful beans for which, the
> > create() method is despatched to the corresponding ejbCreate() method.
> >
> > I hope my understanding is correct. If there is anything wrong, please
> > correct
> > me.  Thanks.
> >
> > Vivek Singh wrote:
> >
> > > The container pools the instances of the beans. When multiple
> > clients call
> > > create()......ejbCreate method of the bean will be called in all the
> > > instances of the pooled bean......then the client is handed over an
> > > EJBObject.
> > > Same happens for statefull session beans...the difference is u can
pass
> > > parameters to the create method and the matching
> > ejbCreate(.....) will be
> > > called in that instance. Same for entity beans.......the instance can
be
> > > cached in this case if used before.
> > >
> > > -----Original Message-----
> > > From: Samuel Abraham [mailto:[EMAIL PROTECTED]]
> > > Sent: Monday, August 14, 2000 6:07 PM
> > > To: [EMAIL PROTECTED]
> > > Subject: Life cycle of beans(Session and entity)
> > >
> > > Hi all,
> > > I have a doubt regarding bean life cycle(Session and Entity).
> > > Assume that many clients are calling the create() method of a
stateless
> > > session beans.
> > > Will the ejbCreate() be called whenever the create() method is called?
> > > What will be the scenario in the case of stateful and entity beans?
> > > TIA
> > > Samuel
> > >
> > >
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> > >
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