About embedded

forum_thread

GWT RPC is throwing serialization exception when I have object db date value

Caused by: com.google.gwt.user.client.rpc.SerializationException: Type 'objectdb.java.util.Date' was not included in the set of types which can be serialized by this SerializationPolicy or its Class object could not be loaded. For security purposes, this type will not be serialized.: instance = Sat Jan 29 00:00:00 PST 2011    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:614)  ... I'm using objectdb 2.2.8 and GWT 2.3.0 with embedded jetty in Eclipse. Stack trace is attached. Any ideas? Is there ...

 
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Update Entity references if we change the type of an entity

Hello, we must change (extend) our entity model and therefor we convert the type of some entities. As example (like in the attached example): We have an EntityA that have a reference to an EntityB. ... is a critical issue. Best regards,   BTC Embedded Systems AG edit ...

 
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Optimization Question

One of our uses for your ObjectDB software is in maintaining the current state of a large number of data objects called tracks. These tracks change very frequently over time (every 10-15 seconds is not unreasonable), but they are also very large complex data structures so it's extremely difficult to identify exactly what fields have changed from one update to the next. Currently the following sequence executes when a track update comes in: - If it’s a new track simply add it to the database.... also consider improving performance by: Using more embedded objects whenever possible. Delaying the delete operations to time ...

 
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java.nio.channels.OverlappingFileLockException

Hello, whenever I re-deploy my web application in Sun Java System Web Server, I get the following exception and the application cannot run anymore. Any clue what I am doing wrong?  I use the file-based db access (local to the web app, as described in your tutorial). Thanks for pointers! Best, Benjamin   ... exception indicates a file locking conflict. In embedded mode the database cannot be opened by more than one user (process / ...

 
issue

Use temporary files to enable very large transactions

We have transactions in which many objects are created. These objects are no longer needed in the current transaction after creation. Unfortunately, we will receive an OutOfMemory exception because the objects are kept in the first level cache of ObjectDB. In the forum thread http://www.objectdb.com/database/forum/921 on post #4 you wrote, that ObjectDB should support very large transactions in further version. Can you implement it that ObjectDB used temporary files? ... to empty the persistence context? Do you use embedded mode or client-server mode? If you were using client-server mode then ... cache page configuration. We use the ObjectDB as embedded db. edit ...

 
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Using Scala collections with ObjectDB

Hi, I cannot see that it is possible to make scala collection classes persistable within ObjectDB. Am I missing something or must  ObjectDB Software Ltd do a specific incorporation of the scala.collection._  api for it to work ? (http://www.scala-lang.org/docu/files/collections-api/collections.html)   /Peter   ... want to leverage the high performance of ObjectDB for an embedded database but want to avoid introducing workarounds that negate this ...

 
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Attempt to store an instance of a non persistable type java.net.URL

ObjectDB 2.3.6_16: The following works in EclipseLink+MySQL and EclipseLink+Oracle: ... It is less efficient than simple types and embedded objects. Support of serialized objects in the Explorer ...

 
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A few questions on object database design

I've been trying to model a database that stores data in an MMORPG. With ObjectDB, a lot of things are easier to perform. Intuitively, I created an entity class called player and stored everything about the player as embeddable classes. However, my colleague questions about this structure, since we would be looking at persisting data from the server every minute or two per player. He has stability issues with the ObjectDB if we are accessing the same table all the time.... disadvantages in each method. In many cases using embedded objects improves performance by eliminating the need to persist and ...

 
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JPA vs JDO - which is more efficient for OneToMany queries?

I'm curious about the trade offs between JDO and JPA. Seems to me that JDO will perform better and be statically typed. For example: Assume there are Customers and Orders.... and ObjectDB can store a collection of references embedded in an entity object. The bottom line is that the difference is not ...

 
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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): ... I forgot to mention we are using ObjectDB in embedded mode. Enhancing was made successfully without any error. ...