I'm currently trying out db4o (the java version) and I pretty much like what I see. But I cannot help wondering how it does perform in a real live (web-)environment. Does ... |
I'm using db4o 6.4.54 in OSGi environment as a model storage. Every time I restart OSGi framework, the database appears to be empty, although the file is there and not empty ... |
Is there any way to completely disable Java security manager?
I'm experimenting with source code of db4o. It uses reflection to persist objects and it seems that security manager doesn't allow ... |
What mechanism does db4o use to instatniate stored objects ?
My class isn't Serializable and doesn't provide zero argument constructor and the only constructor throws NullPointerException when it's argument is null.
In spite ... |
Is there a way to preserve an objest identity in db4o.
Suppose I store a BigDecimal in embedded db4o.
When I read it twice I get two distict objects with the same value ... |
I'm considering to port an application to db4o. The data model consists of lots of small objects with a lot of references between each other. For example, I have a book ... |
I have a data model with a skeleton (metadata) and large data objects. I'd like to keep the skeleton in memory and hold weak references to the data objects. I understand ... |
|
One thing I have continually found very confusing about using an object database like db4o is how you are supposed to handle complex migrations that would normally be handled ... |
As per the title I have three parts to this question...
Is db4o object manager enterprise free?
-I saw a blog post about it being free.
Where can I download it?
-the website is rather ... |
I'm trying to develop a web application that is going to be launched from a HTTP OSGi service, this application needs to use other OSGi service (db4o OSGi), for what ... |
Who can tell me how to use Distinct operation on db4o in Java code. I couldn't find any example in Java.
Thanks!
|
I have a db4o database file. Is there a tool that will generate Java or .NET classes (source) from this database?
|
I need a db4o viewer for a Linux box running Java. I noticed this post was for a .net client, but I don't have Windows and don't intend to.
Is there ... |
I'm struggling to come up with a good way of adding a bidirectional relation in OO model. Let's say there is a Customer who can place many Orders, that is to ... |
I've created a simple webapp using Spring & Jetty, and am creating a hello world JDO test using DataNucleus & DB4O.
I can persist a class no problem, but when I go ... |
I have the following data model class defined:
@PersistenceCapable
public class TestSerializableModelObj {
@Persistent(serialized="true", defaultFetchGroup="true")
private MyPOJO myField;
@Persistent(serialized="true", defaultFetchGroup="true")
private ...
|
Just the basics: I'm using DataNucleus backed with an embedded DB4O database.
If I do this simple test:
PersistenceManager pm1 = persistenceManagerFactory.getPersistenceManager();
PersistenceManager pm2 = persistenceManagerFactory.getPersistenceManager();
...
|
I ran in a strange behavior of db4o. When I persist an Object (implementing Serializable) with an attribute of Serializable[], the Array is only returned once from the store correctly then ... |
I am using db4o and was wondering, how can I get the total number of objects in the database? There isn't an explicit way using the API; however, I can ... |
As a learning tool for DB4o and Java I have started to create a Telephone Directory. To do this I create an instance of a TelephoneDirectory which contains a year and ... |
I'm working with a db4o database and have a database of approximately 1000-5000 objects on Mac OS X, developing in Eclipse Helios.
Currently, I'm retrieving all objects of a certain class:
ObjectSet<Task> query ...
|
Really my question is, if I were to use a nested data structure in oodb would I be placing instance of classes within other instances in the db, or is there ... |
I am trying to store an entity with db4o through an arquillian test case and am getting a DatabaseClosedException:
Test set: com.walterjwhite.address.api.datastore.TestAddressDatastore
Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: ... |
I'm working with db4o embedded for Java (JSE6) running a Servlet app under Tomcat.
Lately I started getting weird exceptions. When trying to save a new object to the DB I get ... |
I have two different Java Applications A and B. They should use the same Database for user management (If the User has an account in Application A, he also has an ... |
I wonder if there's a more beautiful way to store a list of objects then:
ArrayList<Item> itemsList = new ArrayList<Item>;
itemsList.add(new Item(1));
itemsList.add(new Item(2));
ItemDBProvider dbProvider = new ItemDBProvider();
for (int i = 0; i < ...
|
Can someone please explain to me why setting
the Activation Depth seems to have no effect
in the code-sample below ?
This sample creates 'Block'-objects which all have
a number and a child-block.
Since the ActivationDepth ... |
I'm interesting in using DB4O to store the training data for a learning algorithm. This will consist of (potentially) hundreds of millions of objects. Each object is on average ... |
Is it possible to store org.w3c.dom.Node and org.w3c.dom.NodeList as well?
public DocumentElement {
private String name;
private Node thisNode;
private NodeList thisList;
}
If not, is it possible to serialize Node or NodeList into JSON or String ... |
ObjectContainer db=Db4o.openFile(Util.DB4OFILENAME);
db.get(); //doesn't exist
eclipse shows openFile is deprecitated with strike out.
I don't have get or set method.
|
|
|
I'm not really familiar with databases, however; it seems that you are printing a telephone directory, if you can get access to the map you can find the name of the person in the map, correct? I apologize if I am being a bit unclear. You gave yourself the ability to access the year and map in the directory, your result.next ... |
i know i am not good at programming, but i am trying to learn, but also have to submit some projects , that's why i have ask in forums, because there is no body to help me, i am stuck at this error since from last 2 hrs, so dont want to waste more time, that's why i posted it forum, ... |