jdo « jdo « Java Enterprise Q&A

1. Stored procedures vs JDO for data warehousing project    stackoverflow.com

In the old days we used to access the database through stored procedures. They were seen as `the better' way of managing the data. We keep the data in ...

2. JDO not saving object    stackoverflow.com

I have a class Answer, and when I do pm.MakePersistent on an object of that class it doesn't show up in the database. No exception is thrown or anything. When I ...

3. Why "pm.newQuery(Employee.class)" and not "pm.newQuery(Employee)" in JDO?    stackoverflow.com

In this JDO, why is .class needed here?

Query averageSalaryQuery = pm.newQuery(Employee.class);
I would prefer to write this more concise syntax if possible?
Query averageSalaryQuery = pm.newQuery(Employee);

4. Why "import javax.jdo.* "caused error?    stackoverflow.com

I have a class uses the following lines, it works fine in a Google App Engine project:

import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.IdentityType;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;
But when I included this class in another project, it ...

5. Avoid DataNucleus joins?    stackoverflow.com

I'm experimenting with moving a JDBC webapp to JDO DataNucleus 2.1.1. Assume I have some classes that look something like this: public class Position { private Integer id; private String title; } public class Employee { private Integer ...

6. Prepared statement parameter not being set in DataNucleus    stackoverflow.com

I'm trying to insert an Employee object into the database using DataNucleus 2.1.1, but the foreign-key Position parameter is not being set before the "insert" prepared statement is executed. What ...

7. Is there a flat files JDO implementation?    stackoverflow.com

I have a simple app I'd like to use JDO. But I don't want to use any DB back, just regular file system. Before jdo, I had this class it serializes ...

8. Is there an acceptable way to keep these layers/dependencies separate?    stackoverflow.com

I am currently struggling with whether or not I've achieved a good level of separation, or if I've missed the point somewhere, as I am relatively new to learning the disciplined ...

9. Datanucleus JDO setting fields to null    stackoverflow.com

In an attempt to find another issue, my tests came up with the following bit of code.

public class TestPersistance {
 private static final PersistenceManagerFactory PMF = JDOHelper.getPersistenceManagerFactory("datanucleus.properties");
 public static final PersistenceManager ...

10. html value of select option to jdo object    stackoverflow.com

I'm doing an query and getting a list of albums names from my JDO, they are then displayed in a selection menu in html like this

  List<NomeAlbum> results = (List<NomeAlbum>) ...

11. How to return the actual type rather than an Object type from a method that can work for multiple Class types?    stackoverflow.com

Is there any way to modify the findModel method in SubService to return a Foo or Boo type rather than an Object type. I'd like to be able to just call findModel ...

12. Disable auto scanning for JDO classes datanucleus exploded war    stackoverflow.com

When I deploy an exploded war file datanucleus fails with following error

Caused by: org.datanucleus.exceptions.ClassNotResolvedException: Class "JDOTutorial.war.WEB-INF.classes.com.blogspot.jkook.daytrader.jdo.QJDOOrderData" was not found in the CLASSPATH
This does not occur when war is ...

13. DataNucleus ClassNotPersistableException    stackoverflow.com

I hesitate to ask this, because I know it's been pointed out to others that it's a stupid question and that the exception's message is more than clear. And still, I ...

14. JDO: How does PersistenceManager.refresh(Object) deal with dirty fields?    stackoverflow.com

I have an object somePersistentObject that's managed (persistent) by a PersistenceManager with pessimistic transactions (read committed isolation). I make some updates to this object within the current transaction (like... somePersistentObject.setBAC(0.2f);). Now, when ...

15. JDO L2 Cache SingleFieldIdentity    stackoverflow.com

I'm trying to enable L2 cache in my JDO installation. Spring configuration is:

<prop key="datanucleus.cache.level2.type">spymemcached</prop>
<prop key="datanucleus.cache.level2.memcached.servers">localhost:11211</prop>
so prefix is default "datanucleus". The problem is that any object with SingleFieldIdentity is represented by key "datanucleus###" ...

16. JDO - models mapping    stackoverflow.com

I have 3 models: - 2 custom: Event, UserEvent - com.google.appengine.api.users.User User can be registered to many events, and Event can hold many Users. UserEvent has to hold information about events and additional ...

17. Java Cookbook : JDO    coderanch.com

As has been mentioned, JDO is one of several new persistence mechanisms based on "Object Relational Mapping" (another is Hibernate). The basic idea is to make your life easier: instead of writing a whole blob of SQL, you can just deal in *objects*, and have them stored into and loaded from the database (a bit like Entity EJB, but a lot ...

18. Who can give me some message about JDO ???    coderanch.com

O'Reilly has a new book on the very subject: Java Data Objects by David Jordan and Craig Russell. ISBN: 0-596-00276-9 APress has one also, called Using and Understanding Java Data Objects By David Ezzio ISBN: 1-59059-043-0 Haven't checked them out, yet, but I plan to check them both out at some point. Hope this helps.

19. JDO    forums.oracle.com

Hello Colleagues I recently downloaded db40 which I mastered quite easily to create a database of persistent objects. Unfortunately to use this in the capacity which I wish I will have to spend rather a lot of money which I cannot afford to do. I am attracted to an objects database as I wish to embed my database in the application ...

20. JDO Maps problem    forums.oracle.com

21. JDO What a shame    forums.oracle.com