want to develop my project on Google App Engine .I want to use google big table as database. 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. ...
Hi, I'm have a parent-child relation between 2 classes, but the child objects are never stored. I do get an warning: "org.datanucleus.store.appengine.MetaDataValidator checkForIllegalChildField: Unable to validate relation net.vermaas.kivanotify.model.UserCriteria.internalCriteria" but it is unclear to me why this occurs. Already tri...
Hi, I'm quite new to JDO and wanted to ask if it is possible to filter using complex objects. I know that you can do something like this: Query q = pm.newQuery(MyClass.class, "field1 < value"); q.declareParameters("int value"); List results = q.execute(205); Iterator iter = results.iterator(); But assume I have the following situatio...
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 do pm.MakePersistent on other classes, they properly show up in the database. Any idea why this could be happening? ...
Is there any way to query GAE datastore with filter similar to SQL LIKE statement? For example, if a class has a string field, and I want to find all classes that have some specific keyword in that string, how can I do that? It looks like JDOQL's matches() don't work... Am I missing something? Any comments, links or code fragments are ...
I'm working with DataNucleus as part of a Google App Engine project and I'm having a bit of trouble with columns in persistence. @PrimaryKey(column = "user_id") @Column(name = "user_id") @Persistent(name = "user_id", column = "user_id", valueStrategy = IdGeneratorStrategy.IDENTITY) private Key m_id; @Column(name = "user_name") @Persist...
How to store java.util.Calendar field into one column with Datanucleus JDO. By default it is stored into two columns (millisecs, Timezone) with following JDO metadata. field name="startDate" serialized="true" embedded="true" persistence-modifier="persistent" What need to be changed in metadata to sto...
I have the next persistence capable classes: @PersistenceCapable public class AppAccount { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Long id; @Persistent private String companyName; @Persistent List<AppUser> users = new ArrayList<AppUser>(); // Getters and Sett...
Hello, I'm a newbie in JDO. I use eclipse. After I use (PersistenceManager) pm.close for test, now I delete this pm.close. However I still could not find a way to open or create a new one, even after I restarted the computer. Every time, PersistenceManager show this error, Object Manager has been closed And I could not find a way to d...
I am trying to load the full object graph for User, which contains a collection of decks, which then contains a collection of cards, as such: User: @PersistenceCapable(detachable = "true") @Inheritance(strategy = InheritanceStrategy.SUBCLASS_TABLE) @FetchGroup(name = "decks", members = { @Persistent(name = "_Decks") }) public ab...
I have two tables in my oracle database Request and Approver. Every approver has a request. A foreign key protected by a constraint. In my java code using kodo jdo 3.4 I call delete persistant on some or all of the approvers. Then at the end if no approvers are left I call delete persistant on the Request. When I commit I my integrity...
On GAE with Spring/JDO after saving 2 entities (in transaction). On calling getById - entities fetched from data storage. On calling getCount() returns "0" and - on calling getAll() - returns empty collection. @Override public Long getCount() { return ((Integer) getJdoTemplate().execute(new JdoCallback() { @Override public Obj...
I have about 50k entities stored in appengine. I am able to look up an individual record via the GQL admin interface with a query like: SELECT * FROM Pet where __key__ = KEY( 'Pet','Fido') But I'm having trouble figuring out how to do a batch version of this via JDO. Right now I have this: PersistenceManager pm = ...; for(...
My DAO detaches and then caches certain objects, and it may retrieve them with different fetch groups. Depending on which fetch group was used to retrieve the object, certain fields of that object may be available, or not. I would like to be able to test whether a given field on that object was loaded or not, but I can't simply check w...
I understand the sharded counter, here: http://code.google.com/appengine/articles/sharding_counters.html The problem is that a simple counter will not work in my application. I am sorting my entities by a particular variable so I am returned not so much a count, but more of a rank. My current method is: SELECT COUNT(this) FROM Entity.cl...
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); ...
In the following code example how do the user/userParam references relate to the Customer and Account lookups and what is the relationship between Customer and Account? // PersistenceManager pm = ...; Transaction tx = pm.currentTransaction(); User user = userService.currentUser(); List<Account> accounts = new ArrayList<A...
Hi, I'm trying to build my application for GoogleAppEngine using maven. I've added the following to my pom which should "enhance" my classes after building, as suggested on the DataNucleus documentation <plugin> <groupId>org.datanucleus</groupId> <artifactId>maven-datanucleus-plugin</artifactId> ...
Hi, I am currently working on a simple web application through Google App engine using GWT. It should be noted that this is my first attempt at such a task. I have run into to following problem/dilema: I have a simple Class (getters/setters and nothing more. For the sake of clarity I will refer to this Class as DataHolder) and I want...
The question pretty much says it all. If I have a class Class A public class A { ... private List<String> keys; ... } And I want to select all A instances from the DataStore that have atleast one of a List of keys, is there a better way of doing it than this: query = pm.newQuery(A.class); query.setFilter("keys.contains(:...