About performance

forum_thread

How storage works?

I have one Class Car that contains a ArrayList of Wheels. I have already one Car with 4 Wheels attached stored in the DB. If I update my Car adding a new Wheel object is all the Car updated? Or only changed part is updated? By other words, If I have one complex data model and only one part is changed, the Object DB stored the all complex data model or only the changed part? Thanks ... collection is very large and updated frequently there is a performance advantage in defining it as inverse / mapped by. ...

 
forum_thread

ObjectDB vs DB4O comparison

ObjectDB and DB4O are the only two real object database I known. Why didn't you give a comparison between them in JPA Performance Benchmark (JPAB)?  TIA ... Why didn't you give a comparison between them in JPA Performance Benchmark (JPAB)?  TIA Institute ...

 
forum_thread

odb file size doesn't shrink

Hello, why delete from ... doesnt modify size of odb? Even in in embedded mode, and in server mode i use recovery, not recording mode. ... database is not reduced, as it usually better, considering performance, to keep the free space for future extension. ...

 
forum_thread

Update is ignored by ObjectDB

Hi! Sorry for my bad english skills. When I execute fulfilOrder, only Order entity is updated in the database, and User entity remains modified only in code, even if I go: user = smdb.find(User.class, user.id); In this source highlighted lines modifying entity, but not the database. #1 2014-01-25 20:53 Hi! Sorry for my bad english skills. When I execute fulfilOrder, only Order entity is updated in the database, an ...

 
forum_thread

Password Protect Database File

Is there a way to encrypt the odb file so that if hackers somehow steal it they cannot access the data without some kind of password? I would imagine accessing the database from java could just have another connection parameter while accessing from explorer.jar/exe would need to prompt the user for a password for encrypted odb files. ... to encrypt the ObjectDB database file, then for maximum performance use an SSD hard drive with built in hardware encryption ability. If ...

 
tutorial

Step 3: Define an EJB Session Bean

Explains how to define an EJB session bean in an Eclipse Java EE 6 web application. Operations on the database will be performed by an instance of a session bean (EJB) class that we will define in this step: Open the [New Java Class] dialog box by right clicking the guest package node (in the [Package Explorer] window) and selec ...

 
forum_thread

ObjectDB stability after power failure

I'm considering using ObjectDB in a system that is going to be running continuously without support instantly available for many years.  How stable is ObjectDB when it comes to power failures and unattended restarts?  Is database integrity maintained during such events?  I have seen database vendors perform 'kick the plug out' demonstrations of how their product will survive power failures.  Is ObjectDB suitably robust that it won't fail in such situations?    #1 2014-05-21 00:39 I'm considering using ObjectDB in a system that is going to be running continuously without support instantly ...

 
api-jpa

ValidationMode.AUTO

If a Bean Validation provider is present in the environment, the persistence provider must perform the automatic validation of entities.(Enum Constant of javax.persistence.ValidationMode)

 
api-jpa

javax.persistence.spi.ClassTransformer

A persistence provider supplies an instance of this interface to the PersistenceUnitInfo.addTransformer method.(Interface of JPA)

 
forum_thread

Listing large number of complicated objects with paging.

Hi, For last few hours I was working on a problem with bad performance and memory problems with such a simple query: select prod from Product prod order by prod.id ASC Right now I have 55541 'Product' (attached to this post) entities in database and I'm trying to speed listing them with paging. The problem is, that running code that looks like this: ... For last few hours I was working on a problem with bad performance and memory problems with such a simple query: SELECT ...