Hi all When I talk to prospects, customers, journalists, etc. I always introduce JPA as a subset of JDO, which is true in terms of concepts. I think there is a real value in aligning JDO on JPA where possible (annotations, APIs, etc.) or at least in making JPA features as optional in JDO (QL).
I agree with David when he says that JPA is not so popular and most people still use raw proprietary Hibernate. We recently ran a survey among our users: most of them don't even require us to support JPA, and they won't move to JPA when will support it. They are simply happy with JDO and want us to continue to support it. Best Regards, ....: Eric Samson, Founder & CTO, Xcalia Service your Data! -----Message d'origine----- De : Ilan Kirsh [mailto:[EMAIL PROTECTED] Envoyé : vendredi 6 octobre 2006 01:17 À : Andy Jefferson; jdo-dev@db.apache.org; JDO Expert Group Objet : Re: The Future of JDO My personal feeling after reading the JPA spec and two books on EJB 3 / JPA is that JPA is not so weak. It has an excellent query language and API that is very similar to JDO (but more compact). I highly recommend reading "Pro EJB 3 - Java Persistence API" / Apress (despite statements such as "as a result JDO spent most of its time in the persistence underground" and "the writing was on the wall for JDO" - which are very natural for the two authors that work for Oracle). Anyway, I do think that JPA has good chances to succeed. It does take time to achieve a critical mass of implementations and users but it seems that JPA is on the right track. If it succeeds we should be ready. Therefore, I think that Andy's list looks very good as a base for JDO 2.1. Ilan > Totally agree. I would think of the following items > > 1. "persistence.xml". I see no real reason not to allow specification of > classes to be persisted using persistence.xml as an additional way of > creating the PMF. > > 2. Persistence API. There are not many differences between JPA and JDO > methods > so what you propose should be straightforward. Those JDO implementations > that > have/are implementing JPA will know that it is simply putting a wrapper > around their existing JDO method. Why not include in 2.1? > > 3. Query Language. JPQL can be made available via the query "language" > flag in > the existing API (so we add "javax.jdo.query.JPQL" or something as a valid > value). OK the JDO implementation (if supporting this language) will have > to > add a new query language but the hook is there. Could be an optional > feature > in JDO 2.1 ? > > 4. Types. Mandate support for Enums, Calendar when running under Java5, so > all > types that JPA supports are there. Why not include in 2.1? > > 5. Annotations. The donated JDO2 annotations need splitting between > persistence annotations, and ORM. Looking through the JPA annotations some > time ago, it wasn't clear that we can just take theirs and add others due > to > too many missing concepts. What the JDO(3) spec could do is firstly define > the precedence of annotations and metadata (to match the JPA spec > definition), and secondly define how JPA annotations can be used by a JDO3 > implementation. In addition provide JDO2/3 annotations to allow finer > definition. > > -- > Andy
