About string



... eager fetch of non entity collections, such as List<String> ). Improved performance of eager fetch in queries. ...


auto-generated uuid fields

Hello, we're porting a JDO application to ObjectDB which uses uuid-hex generated values. However the page on generated values in your JPA tutorial only mentions numeric generated values, and when we try to use it the error message seems to imply that auto-generating strings isn't supported. Could you confirm whether this is the case? If so it seems an odd omission, given that it's part of both the JPA and JDO standards (JPA Generator.UUID_HEX and JDO value-strategy="uuid-hex") and that the Java language itself supports it (java.util.UUID). #1 2013-04-10 16:48 Hello, we're porting a JDO application to ObjectDB which uses uuid-hex generated values. However the page on ...


Unexpected behaviour upon update. Bug?

This sample does not work as I expect.  Why?  Is it a bug? Below is the complete program. Expect: 3 Get: 4 import java.io.Serializable; import java.util.List; import javax.persistence.*; @Entity public class Update implements Serializable   {     @Id     int i;     int v; ...   public static void main ( String [ ] args ) { ...


Empty query results after JAR creation

Hi, I struggle with a strange issue. I've embedded ObjectDB in a small application to query cases. Within Netbeans everything works fine but when I create a  JAR File and executed via "Java -Jar xyz.jar", I get either empty results or on some cases a "NoResultException" which appears to report the same issue. I've created a small test case (attached zip file) with sample DB to reproduce the issue.  ... = emf. createEntityManager ( ) ; String s = "SELECT c FROM Case c" ;   ...


Query debugging configuration from class

Is there a way to show what queries are actually being executed from within a Java class? I'm getting the exception: Exception in thread "main" [ObjectDB 2.5.4_05] javax.persistence.NonUniqueResultException However, I'm unable to debug it because I don't know what the query's actually searching for. I would like to show what it's actually executing without setting it in xml but rather through Java if possible? ... you should be able to use toString to obtain the query string. ObjectDB Support ObjectDB - Fast Object ...


Multi-thread access to single EM's entities

If my entity classes have synchronized getters and setters, is it reliable for multiple threads to access a single EM's managed entities, as long as only the thread that created the EM interacts directly with it?  I've tested this and it seems to work... but I know better than to depend on the observable behavior of multithreaded code. When I run this example and examine the database, the entity contains the value set by the second thread, as expected.   ...   public static void main ( String [ ] args ) throws InterruptedException { ...



Provides for the specification of generation strategies for the values of primary keys.(Annotation of JPA)


NullPointerException while setting a new property value

Hello, we are using ObjectDB version 2.4.4 and we are unable to resolve following NPE on enhanced entity: java.lang.NullPointerException at com.objectdb.o.ENT.beforeModifyMember(ENT.java:1099) at model.PluginMetaData.__odbSet_maxAllowedDownloads(PluginMetaData.java:1) at model.PluginMetaData.setMaxAllowedDownloads(PluginMetaData.java:268) at model.PluginMetaData.setPluginDescriptor(PluginMetaData.java:94) PluginMetaData looks like this (nothing extraordinary, no relationship to other @entities): ... dbId ;   //persisted info private String id ; private boolean updatesEnabled ; private ...


getObjectById(cls, key)

Looks up the instance of the given type with the given key.(Method of javax.jdo.PersistenceManager)



Instances of the type CollectionAttribute represent persistent java.util.Collection-valued attributes.(Interface of JPA)