About persistence

forum_thread

ODB lost?

I'm new to ObjectDB. While debugging small programs in single-step mode in NetBeans, the ODB appears to get corrupted or lost if I don't invoke close on EntityManager. If I re-run my program and get a new EntityManager, the instance behaves as if the data that was persisting is somehow gone. I noticed in the file system, indeed, the .odb file is gone, but there are <name>_<v>.odb files where <name> is the name of my odb and <v> is apparently a version number. Is there any way to recover <name>.odb? #1 2011-03-18 23:11 I'm new to ObjectDB. While debugging small programs in single-step mode in NetBeans, the ODB appears to get corru ...

 
forum_thread

Optimistic Locking

We are having problems with optimistic locking.  I made a simple test case to try to induce an optimistic lock. #1 2010-08-11 16:03 We are having problems with optimistic locking. I made a simple test case to try to induce an optimistic lock. ...

 
manual

Chapter 3 - Using JPA

Explains how to store, retrieve, update and delete entity objects using JPA.... explains how to manage ObjectDB databases using the Java Persistence API (JPA). The first two pages introduce basic JPA ...

 
forum_thread

Import data from MySQL

Hi, I tried the objectdb in my research, find it very easy to handle without setting up xml files. However, I cannot find the import/export functions between other database, then how can I transfer mysql data into objectdb? When I use explorer.exe to browse the database in objectdb, eclipse tells me another app occupy it, then how can objectdb support multi-thread? #1 2011-05-17 04:11 Hi, I tried the objectdb in my research, find it very easy to handle without setting up xml files. ...

 
forum_thread

createNamedQuery throws wrong exception

Hello I'm tying to use ObjecDB with spring-data for JPA and there is an issue where spring-data checks for existance of named query which does not exist yet. Based on JPA specification ... for executing a named query * (in the Java Persistence query language or in native SQL). * @param name the name of a ... name ) ; however ObjectDB throws javax.persistence.PersistenceException instead of IllegalArgumentException which ...

 
forum_thread

null pointer exception in objectdb-2.4.4_06

I have the following stack trace.  Is this a null ptr in our code or in the object db code? #1 2012-12-07 14:02 I have the following stack trace.  Is this a null ptr in our code or in the object db code? Failed to ...

 
api-jpa

javax.persistence.Embeddable

Defines a class whose instances are stored as an intrinsic part of an owning entity and share the identity of the entity.(Annotation of JPA)

 
forum_thread

Understanding limitations of schema evolution

Hi, I am trying to understand the limitations of schema evolution and have read the material on http://www.objectdb.com/java/jpa/entity/schema as well as the link therein regarding manual schema update when changing a field’s name Yet, i am confused regarding how to handle the case where one re-factors a class by moving one if it's Fields to a different class. Is this case managable? Thanks #1 2014-10-31 12:31 Hi, I am trying to understand the limitations of schema evolution and have read the material on http://www.objectdb.c ...

 
api-jdo

javax.jdo.identity.SingleFieldIdentity

This class is the abstract base class for all single field identity classes.(Class of JDO)

 
forum_thread

Delete object from collection versus delete from JPQL

I'm a newbie, so this is a pretty fundamental question. I'm not sure if there is a bi-directional relationship between the objects in memory and ObjectDB.  I know I can modify the objects and use persist() to write them to the database.  But does running a JPQL update or delete alter the in-memory objects? There are cases where the JPQL syntax is more expressive than operating on a collection, but I'm not sure if that will alter my program state.  Will it? Thanks, Lee  #1 2014-03-24 22:25 I'm a newbie, so this is a pretty fundamental question. I'm not sure if there is a bi-directional ...