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Questions tagged [datanucleus]

DataNucleus AccessPlatform is an implementation of the JDO and JPA API specifications for Java object persistence, as well as providing a REST API. It is fully standards-compliant, and supports persistence to RDBMS, ODBMS, documents (XML, Excel, ODF), web-based (JSON, Amazon S3, GoogleStorage), map-based (HBase, Cassandra), document-based (MongoDB), graph-based (Neo4j) as well as some others (LDAP).

DataNucleus AccessPlatform is an implementation of the JDO and JPA API specifications for Java object persistence, as well as providing a REST API. It is fully standards-compliant, and supports persistence to RDBMS, ODBMS, Documents (XML, Excel, ODF), Web-based (JSON, Amazon S3, GoogleStorage), Map-stores (HBase, Cassandra), document-based (MongoDB), graph-based (Nep4j) as well as some others (LDAP).

890 questions
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Creating new Datastore entities with optimistic locking (Google App Engine Java / JPA)

I have a JPA entity class User with a username @ID and no parent entity group. I need to make sure that when two parallel transactions try to persist a new User with the same username, only one is committed and the other one is rolled…
David Geiger
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JPA on Google App Engine: When calling persist(...), does it always happen in a transaction?

In my application I am persisting an entity that has a number of unowned children. It seems that the call to persist which does the persisting of the entity and all children happens inside a transaction because I get an error when I do not enable…
Marc
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Unable to get ID of newly-created JDO persistent entity using GAE/J DataNucleus plug-in version 2.1.2

My problem I am porting my application from version 1.x to 2.0 of the DataNucleus plug-in for GAE/J using the new 1.7.5 GAE/J SDK. This changes my JDO version from 2.3 to 3.0.1. My persistent entity class has a primary key of type encoded string,…
Ian Marshall
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Persistence manager failing to instantiate

I have a web application project using gwt and using google app engine to store my data. When I run my project I get the following error: WARNING: Error for /proj/saat java.lang.NoSuchFieldError: NUCLEUS_CONTEXT_LOADER at…
BBB
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Datanucleus JDO Mongodb - Child of abstract in map value not persisted

I am using Datanucleus/JDO to persist objects in a MongoDB DB. I try to persist an object containing a Map, which value type is an abstract class. When I try to persist an instance of that object, fields of the abstract class are persisted, but not…
Bertrand88
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Stackoverflow when querying document with cycle reference using @DBRef

My Application uses MongoDb with Spring-Data. My User.java is as follows. User{ //other fields @DBRef List requests; } Request.java is as follows. class Request{ @Id private ObjectId id; @DBRef private User…
titogeo
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GAE: Access denied exception causing error on persistence provider

I just upgraded to GAE SDK 1.7.1 and now I'm trying to use JPA 2 in my [former] functioning project. When I try to use the Entity Manager it throws the following exception: java.lang.ExceptionInInitializerError at java.lang.Class.forName0(Native…
Roberto
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how to deal with datastore-indexes app engine?

for this example LINK i try to make it but this exception occurred ?? com.google.appengine.api.datastore.DatastoreNeedIndexException: no matching index found. The suggested index for this query is:
Start
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How to set loglevel of the Appengine DataStore in Java

I have a logging.properties file in my Java AppEngine project (using java.util.logging) that looks like this: # Set the default logging level for all loggers to WARNING .level = INFO # tighten logging on the DataNucleus…
Animesh
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HBASE ERROR: Failed setting up proxy interface org.apache.hadoop.hbase.ipc.HRegionInterface

I am currently trying to work on HDFS and HBASE. The Hadoop and HBASE are properly installed on a machine and my application runs perfectly when hosted on the same machine. But when hosting on another machine. On first hit to HBASE I get an error…
devsri
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How do I make a JDO query using contains()?

I have a class with an enum as instance variable: public enum Races { Human, Elf, Orc, Troll } @PersistenceCapable(detachable="true") public class Crafter { @PrimaryKey @Persistent(valueStrategy =…
user1091789
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Transitioning from Castor to JPA

I am trying to make my java application more standards compliant and one of the biggest issues i am facing is transitioning our ORM framework from Castor JDO to a JPA implementation (thinking either Hibernate or DataNucleus). We have our own…
Peter Anthony
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How to prevent multiple RPC RunQuery calls on single JDO Query execute()?

I have configured Appstats on my Java Appengine application and noticed that a single JDO Query which returns several objects results in a separate RunQuery RPC call for every object retrieved by the Query. Shouldn't a Query be done in a single RPC…
Jorge Cardoso
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Salesforce's Database.com and Google App Engine via JPA

Currently i try to connect (via JPA/Datanucleus) with an application, hosted by Google App Engine, to the database service of database.com (Salesforce) After many hours of reading and trying, i could not find any solution. So, is it even…
KotakeTetsuya
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InvocationTargetException: Plugin (Bundle) "org.datanucleus" is already registered

I am trying to follow the DataNucleus tutorial for JDO. I am using Maven and I have followed the instructions available here for the enhancer. However, I am getting the following error: [datanucleus:enhance] Could not transfer metadata…
Jérôme Verstrynge
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