http://www.onjava.com/pub/a/onjava/2001/05/10/ejb.html
-----Original Message----- From: Ramakrishna N [mailto:[EMAIL PROTECTED]] Sent: Wednesday, March 06, 2002 7:06 AM To: Subject: Re: Can a CMP EJB be a CMP field inside another CMP EJB Hi, You can see it from a database perspective also. Say you have a Customer and he has an Address. Now when you design the database schema for this scenario, would you model Address as a seperate entity ? If you do that, then how are you gonna differentiate between addresses (which address corresponds to whom). So you need to have a foreign key imported into your Address table, more clearly, your Address does not exist without a Customer (if it exists it doesnt make any sense for the above stated reasons). So, this is dependent on Customer and hence this is bound to be modeled as a dependentObject(LocalInterface, EJB2.0). An enity is a corse grained object that can exist without depending on anybody whereas a fine grained object meaning that the finer-details of an entity (captured into a logical object called fine-grained-object) are put in a dependent object whose life-cycle is bound to be dependent on an Entiy or other finer-detailed-object of an entity. To summarise, Corse-grained object : The obvious data of an entity Fine-grained object : The obvious finer/"microscopic" details captured into a logical object and (should be) stated to which entity does the details(logically abstracted FINER DETAILS) in this object belong to. Hope this opens some avenues regarding the solution to your issue. Regards, Kris -----Original Message----- From: Ashwani Kalra [mailto:[EMAIL PROTECTED]] Sent: Wednesday, March 06, 2002 4:55 PM To: [EMAIL PROTECTED] Subject: Re: Can a CMP EJB be a CMP field inside another CMP EJB Hi, 1.Consider an example. if A is completely dependent on B for its existance then A is modelled as dependent object of B(entity bean) for example . Customer entity bean may have dependent object Address. If there is no customer then there can be no Address. 2.Question is not of optimisation of colocated EJBs but remote client accessing two separate EJBs. Resulting in network traffic. Also if you model them (Customer and Address) as separate EJBs, then you may not have control on how they should be created. Client may try to create address ejb which cannot exist without a customer EJB. Regds Ashwani -----Original Message----- From: A mailing list for Enterprise JavaBeans development [mailto:[EMAIL PROTECTED]]On Behalf Of shreedhar Sent: Wednesday, March 06, 2002 11:06 AM To: [EMAIL PROTECTED] Subject: Re: Can a CMP EJB be a CMP field inside another CMP EJB I have few similar questions. CMP 1.1 is version what I use. Please answer this questions with CMP 1.1 perspective 1) How do you exactly classify Entity Beans as Fine Grained - Coarse Grained. I see very much confusing definitions from various sites. Dependent Objects adds to this confusion. 2) As per my understanding Address is a dependent Object. Why not we implement it as an Entity Bean. I guess all the application server has various optimizations when it comes to communication between Co-Located Entity Beans. 3) I was goin thru AggregateEntity Pattern. I guess the pattern was introduced without assuming various optimization done by the App. Servers. The pattern directs to use a Coarse Grained Object composed of various Fine Grained Object. And the Aggregate Entity(EJB) will have Coarse Grained Object as one of its instance(one of strategy). In this case how will I map the Coarse Grained Object to the persistence Schema. -----Original Message----- From: Ashwani Kalra [mailto:[EMAIL PROTECTED]] Sent: Tuesday, March 05, 2002 2:12 PM To: [EMAIL PROTECTED] Subject: Re: Can a CMP EJB be a CMP field inside another CMP EJB Looks some design problem. Fine grained objects such as address whose life cycle is dependent on other ejb. They are better implemented as dependent objects. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Cheers Ashwani Kalra Sr. Mem. Dev. Staff Aithent Technologies India http://www.geocities.com/ashwani_kalra/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -----Original Message----- From: A mailing list for Enterprise JavaBeans development [mailto:[EMAIL PROTECTED]]On Behalf Of Sanjeev Verma Sent: Tuesday, March 05, 2002 1:20 PM To: [EMAIL PROTECTED] Subject: Can a CMP EJB be a CMP field inside another CMP EJB Hi all lets say we have two CMP EJBs (1.1 spec), Person and Address. 1. Can the person EJB have a cmp field as Address EJB? (In EJB 1.1) 2. If yes, what will be the create statement for the table that will hold the person data look like. I basically mean to ask the data type of the Address column. 3. If this was with reference to EJB 2.0, can I still have point 1? I DO NOT mean/want to use <cmr-field>. Thanx Sanjeev =========================================================================== 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". =========================================================================== 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". 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