About number

forum_thread

Selecting random rows

Hello is there way to get random rows? Functions line rand(), random(), newid() doesn't work ;/ for example: em.createQuery("SELECT s FROM StawkaVat s ORDER BY rand()").setMaxResults(5).getResultList(); gives exception: ... You may use setFirstResult with a random number. ObjectDB Support ObjectDB - Fast Object ...

 
issue

Entity Version History

ObjectDB manages automatic entity versioning (for optimistic lock purposes). Every entity object modification is reflected by a new version number. Previous values in the entity object that are overridden by new values, however, are discarded. Some applications may benefit from the ability to go back in time and view old versions (and old values) of entity object. Future versions of ObjectDB should support archiving old versions of specific entity classes.... entity object modification is reflected by a new version number. Naturally, previous values in the entity object that are overridden by ...

 
forum_thread

Embedded mode usage question

Hi there ! ... server) mode for a web app or web service, accessed by a number of end-users (consumers).   Thanks, Dmitri ...

 
forum_thread

Specify location of persistence.xml

Is it possible to tell objectdb explicitly where the persistence.xml is located? ... as other Providers use also a persistence.xml I exceed the number of persistable classes, as I have one subproject for each persistence ...

 
api-jdo

replacingFloatField(pc, field)

The replacement value of the field in the calling instance.(Method of javax.jdo.spi.StateManager)

 
forum_thread

internal object DB locking in an embedded multi threaded application

Hi, we are using Embeded objectDB 2.4.4_06 in a highly multithreaded concurrent manner and we have noticed a performance problem in our application that seems to be attributed to ObjectDb's internal locking. When profiling our app in JVisualVm we notice a large number of threads are blocked and when doing a threaddump we notice that they are all blocked in the same place: ... When profiling our app in JVisualVm we notice a large number of threads are blocked and when doing a threaddump we notice that they ...

 
forum_thread

Compile time enhancement using build.xml of a Netbeans web application

Does anybody have a complete, working example of the adaptations required in the build.xml of a Netbeans web application project to specify ObjectDB compile time enhancement, for both single file and whole project compilation ? The ObjectDB 2.3 manual gives the following tip: ... of Netbeans, that is included into build.xml, offers a number of empty targets to override in build.xml, such as -post-compile ...

 
api-jdo

providedObjectField(pc, field, currentValue)

The value of the field requested to be provided to the StateManager.(Method of javax.jdo.spi.StateManager)

 
api-jdo

providedBooleanField(pc, field, currentValue)

The value of the field requested to be provided to the StateManager.(Method of javax.jdo.spi.StateManager)

 
api-jdo

storeDoubleField(fieldNumber, value)

Store one field into the field manager.(Method of javax.jdo.spi.PersistenceCapable.ObjectIdFieldConsumer)