Hi,

Allow me to ask some silly question please,

recently , I come across JDO (Java Data Object) specification, it appears to me that in general JDO and hibernate are rather similar , although I am not very sure about it functionality and persitence concept as both are trying to make the life of java developer much easier , by trying to have alternative to EJB entity bean approach.

What i am interested to know it is also whether JDO could be external access as oppose to hibernate concept.

Please don't get me wrong as if I am trying to downgrade hibernate in anyway , All i need to know is the comparison and some feedback from those who reply.


Thanks

Hard to answer but.
JDO:
1) JDO is basic in its relational mapping abilities and access language. Its feature set is well below that of Hibernates.
2) It is a standard but similar to the motivation behind Entity Beans specification enhancements, JDO 2 spec currently underway is trying to address the most glaring problems.
3) Its focus os not just relationa DBs but Object databases as well.

Hibernate:
1) Full rich relational mapping abilities - no Object DB mapping, eg, its is a complete and focused ORM while JDO is not.
2) It is its own standard. It is being built by people who apply the tool in practice. Its development has been carefully designed to address real problems and requirements in the ORM area.
3) In my view it is not competing with JDO. it is competing with the large ORM vendors such as Oracle TopLink.

Most (likely All) of the JDO vendors provide vendor extensions. These extensions are there as JDO has its limitaions. The vendors are quick to state you should use a standard but once a client uses an extension (and they will) your locked into that vendor thus all benefits for having/using a standard are gone.

Personally I think there is space for a full and rich ORM standard as well as the JDO standard. Hibernate is effectively the default Java standard due to market adoption. I don't think it is necessary but maybe one day it will be formalised as a JSR - who knows.

Dear David,

Thanks a lot , I really appreciated that , I do hope hibernate would one day formalised as JSR too,
lets look forward for that great moment .