As described in this article there is a strong need for fetch plans is JPA. Some people, even within the JPA expert group, seem to think there is no need for a specific API for fetch plans, they could be covered by criteria APIs. I personnaly think that a fetch plan is not a criteria or a filter, it is something related but different. Regarding this feature, data access technologies coming from the JDO world have some advantages, as this feature has been discussed with the JDO expert group since a long time.
Obviously, fetch plans are even more important when dealing with a disconnected data access model, like in Data Services. Some partial reconnection could be allowed when relationships are unknown during navigation, but current network technologies certainly cannot support full lazy loading over the Internet.
Wednesday, September 3, 2008
The need for fetch plans
As described in this article there is a strong need for fetch plans is JPA. Some people, even within the JPA expert group, seem to think there is no need for a specific API for fetch plans, they could be covered by criteria APIs. I personnaly think that a fetch plan is not a criteria or a filter, it is something related but different. Regarding this feature, data access technologies coming from the JDO world have some advantages, as this feature has been discussed with the JDO expert group since a long time.
Obviously, fetch plans are even more important when dealing with a disconnected data access model, like in Data Services. Some partial reconnection could be allowed when relationships are unknown during navigation, but current network technologies certainly cannot support full lazy loading over the Internet.
Obviously, fetch plans are even more important when dealing with a disconnected data access model, like in Data Services. Some partial reconnection could be allowed when relationships are unknown during navigation, but current network technologies certainly cannot support full lazy loading over the Internet.
Tuesday, September 2, 2008
Versioning of objects
Versioning of persistent objects is a complex probem. People, mostly in the finance industry, are looking for solutions to this since years (see this post for instance). It seems there are now some solutions emerging, like Envers from RedHat/JBoss.
It is not clear from their web site if Envers supports JPA or only Hibernate, it seems to me it is limited to Hibernate.
LiDO, the old mapping technology of Xcalia, used to support this powerful feature in its version 2 (2003). This is something we have deprecated when we decided to open our data access engine, in order to support any kind of data sources, not only RDBMS.
Now that ORM is well established, and the basci problem is almost solved, it is the time to add features with business added-value like versioning.
It is not clear from their web site if Envers supports JPA or only Hibernate, it seems to me it is limited to Hibernate.
LiDO, the old mapping technology of Xcalia, used to support this powerful feature in its version 2 (2003). This is something we have deprecated when we decided to open our data access engine, in order to support any kind of data sources, not only RDBMS.
Now that ORM is well established, and the basci problem is almost solved, it is the time to add features with business added-value like versioning.
Versioning of objects
Versioning of persistent objects is a complex probem. People, mostly in the finance industry, are looking for solutions to this since years (see this post for instance). It seems there are now some solutions emerging, like Envers from RedHat/JBoss.
It is not clear from their web site if Envers supports JPA or only Hibernate, it seems to me it is limited to Hibernate.
LiDO, the old mapping technology of Xcalia, used to support this powerful feature in its version 2 (2003). This is something we have deprecated when we decided to open our data access engine, in order to support any kind of data sources, not only RDBMS.
Now that ORM is well established, and the basci problem is almost solved, it is the time to add features with business added-value like versioning.
It is not clear from their web site if Envers supports JPA or only Hibernate, it seems to me it is limited to Hibernate.
LiDO, the old mapping technology of Xcalia, used to support this powerful feature in its version 2 (2003). This is something we have deprecated when we decided to open our data access engine, in order to support any kind of data sources, not only RDBMS.
Now that ORM is well established, and the basci problem is almost solved, it is the time to add features with business added-value like versioning.
JDO Instruments v3
New version is released. This is an open source ODBMS, compliant with JDO.
http://www.theserverside.com/news/thread.tss?thread_id=50283.
http://www.jdoinstruments.org/
http://www.theserverside.com/news/thread.tss?thread_id=50283.
http://www.jdoinstruments.org/
JDO Instruments v3
New version is released. This is an open source ODBMS, compliant with JDO.
http://www.theserverside.com/news/thread.tss?thread_id=50283.
http://www.jdoinstruments.org/
http://www.theserverside.com/news/thread.tss?thread_id=50283.
http://www.jdoinstruments.org/
Saturday, August 23, 2008
Data Services blog is back
You didn't see any activity on this blog since last June. I first get married beginning of July, then was on vacation in the South of France and then recently moved to the US in the Washington DC area.
I now have Internet at home since yesterday and I'm ready to go on with all these exciting news and trends about Data Services and Data Access in general.
Stay tuned! Eric Samson.
I now have Internet at home since yesterday and I'm ready to go on with all these exciting news and trends about Data Services and Data Access in general.
Stay tuned! Eric Samson.
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