Your understanding is correct. In addition to the reason you mentioned, providing a primary key class also insures a degree of type safety you cannot get with primative data types.
--Victor
Manoj Kumar wrote:
Hi, But i think as per the design patterns , one should always use the Primary key class so that if at a later point of time your primary key changes to a composite primary key then the impact on the code will be minimum. Though the possibility of change in primary key is very little. I donot think that having the own primary key introduces any overhead in performance other than the bit of extra coding which the developer has to do, Please make me correct if i am wrong in my understanding...Thanks Manoj Ashwani Kalra wrote:Hi, Hicks you are right. He doesnt need compound key. <prim-key-class>personal.ejb.learning.cmpbean.AccountCMPPK</prim-key-class> change to <prim-key-class>java.lang.Integer</prim-key-class> will suffice I think Do not use personal.ejb.learning.cmpbean.AccountCMPPK class as primary key. Cheers ______________________________________________ Ashwani Kalra HomePage : http://www.geocities.com/ashwani_kalra/ ________________________________________________ "Hicks, James" <James.Hicks@LMBE To: [EMAIL PROTECTED] RRY.COM> cc: (bcc: ashwani.kalra/Polaris) Sent by: A Subject: Re: Problem with Return type of Abstarct get/set methods in mailing list for CMP E ntity Beans Enterprise JavaBeans development <EJB-INTEREST@JAV A.SUN.COM> 12/23/2002 11:56 PM Please respond to "Hicks, James" The problem now is that the account number field is a custom type. Your database and application server know nothing about it, so it stores it in binary format in your database. Why are you using a custom PK class? I see that you only have a single field in the class, why not make your account number field an int or long and use either a java.lang.Integer or java.lang.Long as the primary key class. This would solve your problem easily. If on the other hand you want to use a custom PK class, change the account number field back to a int and make the changes that I gave you in the first email. Your app server should be match the fields in the pk class to the fields in the bean class. I have seen very few instances where a custom PK class was actually needed. They usually come into play when integrating with existing database designs. James Hicks -----Original Message----- From: Manoj Kumar [mailto:[EMAIL PROTECTED]] Sent: Monday, December 23, 2002 11:30 AM To: Hicks, James Cc: [EMAIL PROTECTED] Subject: Re: Problem with Return type of Abstarct get/set methods in CMP Entity Beans One more factor which i noticed after changing the return type 'int' to the primary key class 'AccontPK' is that i could deploy my CMP bean however while calling the create method on the bean i was getting data type inconsistency. My underlying table was having the following structure SQL> desc account Name Null? Type ------------------------------- -------- ---- ACCNUMBER NUMBER(7) OWNERNAME VARCHAR2(30) BALANCE NUMBER(7) When i changed the structure of my table to SQL> desc account Name Null? Type ------------------------------- -------- ---- ACCNUMBER RAW(1000) OWNERNAME VARCHAR2(30) BALANCE NUMBER(7) then i could run my bean successfully........ I could not get what was wrong with my earlier table definition. After creating the record when i checked the record in table 'account' , accountnumber column was having the following value. AccountNumber Column ACED000573720028706572736F6E616C2E656A622E6C6561726E696E672E636D706265616E2E4669727374434D50504BB6AD9841A6518F7B0200014900096163634E756D626572787000000066 It seems that i made some mistake in the deployment descriptor... Any suggestions in this regard are welcome !!!!!!!! Thanks Manoj "Hicks, James" wrote: It would help to see your deployment descriptors. That is probably where your error is. James -----Original Message----- From: Manoj Kumar [mailto:[EMAIL PROTECTED]] Sent: Monday, December 23, 2002 10:17 AM To: [EMAIL PROTECTED] Subject: Problem with Return type of Abstarct get/set methods in CMP Entity Beans Hi, I have created a 'Account' Entity bean having a Primary Key class 'AccountPK' which has a AccountNumber field. My bean class has abstarct set/get methods for AccountNumber also. Signatures of these methods is as under public abstract int getAccNumber(); public abstract void setAccNumber(int accnumber); When i tried deploying the Bean in weblgic 7.0, i got the exception saying that the return type of the abstarct methods getAccountNumber should be of primary key AccountPK and not the int. However, all the examples which i could find in tutorials and Books says that the return type should be the data type of the field which in this case is int. Thanks in advance! Manoj Kumar. =========================================================================== 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". The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination, or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you receive this in error, please contact the sender and delete the material from all computers. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination, or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you receive this in error, please contact the sender and delete the material from all computers. ------------------------------------------------------------------------ Name: InterScan_Disclaimer.txt InterScan_Disclaimer.txt Type: Plain Text (text/plain) Encoding: 7bit=========================================================================== 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".
