Category Archives: Uncategorized

DN v5 : JPQL FROM JOIN to another “root” entity

A vendor extension now available in DataNucleus v5 is for JPQL’s ability to JOIN to other entities. In standard JPQL you can only add a JOIN through a relation. For example SELECT p FROM Person p JOIN p.address a WHERE … Continue reading

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JDO 3.2 JDOQLTypedQuery : improvements relative to DN extension

Now that JDO 3.2 standardises the “typed query” mechanism that we prototyped in DataNucleus v3.x and v4.0/v4.1 it is worth mentioning the additions to the API that are present in the JDO 3.2 variant. StringExpression This has gained the following … Continue reading

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JDO 3.2 Revisions to Query API

Here we present some changes to the JDO Query API that are coming in version 3.2 of the spec. Comments should be directed ASAP to the Apache JDO mailing list if you want any changes to make it in to … Continue reading

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What does open-source owe you?

If you ever embark on a period of time writing open source (free) software you’ll almost certainly come across many different attitudes in the people who choose to use this software. There will be some people who’ll actually say thanks … Continue reading

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Performance – effect of various features

2 years ago I made a post about performance/benchmarking, and the fact that some groups like some magic black and white¬†“X is better than Y” (and that there is only one measure of performance so it doesn’t matter what object … Continue reading

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Enhancing in v3.2

Whilst a “final release” of version 3.2 of DataNucleus is still some way off, some important changes have been made to the enhancement process that people need to be aware of, and can benefit from. JDO : Ability to enhance … Continue reading

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GAE/J and DataNucleus v3 – Part 2

In the previous post we saw some initial changes to make GAE/J DataNucleus plugin work with the latest version of DataNucleus plugins. In this post we describe some further features of interest to GAE users that they weren’t able to … Continue reading

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TJDO has left the building

As anyone who has been using DataNucleus (and JPOX before it) for some time will know, it all started out (in 2003) as TJDO. This project was forked to provide all of the missing functionality that JDO requires and users … Continue reading

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Welcome to the DataNucleus

DataNucleus is a project providing Open Source software for use in the Java language, for persisting objects to datastores. DataNucleus AccessPlatform 1.0 (Faraday) was released on September 1st 2008, providing JDO/JPA persistence to RDBMS, db4o, XML, Excel, LDAP, NeoDatis and … Continue reading

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