what is the different jpox and data nucleus implementation of JDO?
what is the different jpox and data nucleus implementation of JDO? both also free implementation right? ...
jdo
Many-to-Many relationship in DataNucleus (JDO) doesn't persist
Hi, I don't manage to persist a many-to-many link with DataNucleus using JDO. I have two classes Book and Shop. This is the orm mapping file: <?xml version="1.0"?> <!DOCTYPE orm PUBLIC "-//Sun Microsystems, Inc.//DTD Java Data Objects Metadata 2.0//EN" "http://java.sun.com/dtd/orm_2_0.dtd"> <orm> <package name="com.my...
Java App Engine Datastore: How to query fields of object's inherited classes?
AppEngine 1.2.2. I define a class Product like so: @PersistenceCapable(identityType = IdentityType.APPLICATION, table="Products") public class Product { public Product(String title) { super(); this.title = title; } public String getTitle() { return title; } @Persistent String title; @PrimaryKey @Persistent(valueStrateg...
App Engine Class With Children Of The Same Type
I'm trying to save a tree structure in app engine. My class has a parent and a list of children of the same type. Everything works until I add the children property. There are no errors when I call pm.makePersistent(), but the object is not saved. Does anyone know why this doesn't work? This is my class. I'm using App Engine versio...
JDO integration with hibernate
in JPA, to use hibernate, the only thing need to do is moodify persitence.xml and add in hibernate configuration. May i know with JDO, can just by modifying jdoconfig.xml, able to integrate with hibernate? any reference or example on this? ...
Google App Engine / JDO : is there a session cache?
Since there is no way to join tables using Google App Engine datastore, I loop over a list of entities and look up the related entities one-by-one using the foreign key value. for (Employee staff: staffList){ Employee manager = pm.getObjectById(Employee.class, staff.getManagerId()); } There is a good chance that I will be needing ...
self join in google app engine (java)
Hi I have modified the guestbook example shipped with google app engine (java) to include a parent-child relationship using some sort of a 'self join'. Now my greeting.java file looks like this package guestbook; import java.util.Date; import java.util.List; import javax.jdo.annotations.IdGeneratorStrategy; import javax.jdo.anno...
Problems while saving a pre-persisted object in Google App Engine (Java)
I am having problems while saving a pre-persisted JDO object in google-app-engine data store. Basically, in one servlet, I create the object and save it. In another servlet, I read the object, set a bunch of properties and try updating it. The update is through a makePersistent call on PersistenceManager. There is no exception being thro...
Many to many relationship in java google ap engine
how would i go about creating a many-many relationship among data objects in google app engine (using jdo) The app engine page talks about 1-many and 1-1 but not many-many. Any code example will be highly appreciated ...
Google App Engine / JDO : store computed values
Since I cannot do JOIN queries against the App Engine Datastore, I would like to denormalize my entity objects a little to include computed values, in effect creating something like a function-based index. @Persistent Employee manager; @Persistent // de-normalized stored join value Integer managerDepartmentCode; This works fine,...
Why put a DAO layer over a persistence layer (like JDO or Hibernate)
Data Access Objects (DAOs) are a common design pattern, and recommended by Sun. But the earliest examples of Java DAOs interacted directly with relational databases -- they were, in essence, doing object-relational mapping (ORM). Nowadays, I see DAOs on top of mature ORM frameworks like JDO and Hibernate, and I wonder if that is really a...
updating an object with JDO and GAE
So, I'm creating a small web app using Wicket that will run on the google app engine. I'm using JDO, and so far have no problems persisting data (inserts) or querying data those same data objects. Maybe I'm missing some basic thing, I'm trying to take one of those persisted objects, change two values and then I want that modified objec...
Build Query: q.setFiler("parentID == 123 && language == en")
Hello, I would like to build a query which looks like that query.setFilter("parentID == 123 && langauge == en") because I have an owned OneToMany Relationshiop between Article and Description and I am looking for an effektiv way to get a specific description. Thanks, Ralph @PersistenceCapable(identityType = IdentityType.APPLICATIO...
JDO vs JPA for Java on Google App Engine
I want to develop my project on Google App Engine with Struts2. For the database I have two options JPA and JDO. Will you guys please suggest me on it? Both are new for me and I need to learn them. So I will be focused on one after your replies. Thanks. ...
duplicate jdoconfig.xml on classpath during unit tests in Intellij IDEA (9.x pre-release)
As described here, IDEA is adding the jdoconfig.xml to the class path twice during unit test runs. Can anyone suggest a work-around for this? /System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home/bin/java -Dgwt.args=-gen /Users/jgc/Library/Caches/IntelliJIDEA9M1/gwt/recipes.recipesea699bb7/Recipes.4dd34334/test/gen -out /...
How can I implement Session-Per-Request ("Open-Session-In-View") pattern using JAX-RS?
I'm using JDO on AppEngine with Restlet + JAX-RS extensions. In my sub-resource locator class I load the entity in the constructor. Then for the various methods I used the data. If I close the PersistenceManager before returning from the Constructor, collections of one-to-many fields are not initialized and remain null. I read about "d...
Java Google App Engine Datastore: 'IN' operator available on JDO query filters, as with Python?
This page describes an 'IN' operator that can be used in GAE Datastore to compare a field against a list of possible matches, not just a single value: However this is for Python. In Java (App Engine 1.2.5), trying query.setFilter("someField IN param"); on my javax.jdo.query fires a JDOUserException 'Portion of expression could not b...
updating "nested" objects with JDO on Google App Engine
I'm having trouble figuring out the proper way to update "nested" data using Google App Engine and JDO. I have a RecipeJDO and an IngredientJDO. I want to be able to completely replace the ingredients in a given recipe instance with a new list of ingredients. Then, when that recipe is (re)persisted, any previously attached ingredients...
full-text search using Google App Engine and JDO?
I'm using Google App Engine (Java) with JDO. How can I do the JDO equivalent of select * from table where field like '%foo%' The only recommendation I have seen so far is to use Lucene. I'm kind of surprised that something this basic is not possible on out-of-the-box GAE. ...
JDO for Google App Engine: escaping quotes
How do I escape parameters of queries in JDO (Google App Engine)? For example, how do I make the next snippet safe, if the variable name may contain unsafe chars as single quotes (') PersistenceManager pm = ...; String query = "select from Person where name='"+name+"'"; List<Shortened> shortened = (List<Shortened>) pm.newQuery(query).e...