persistence

Why my data does not get persisted?

I am using JPA and Java Embedded DB in my application. I try to write some data to the database and when i try to read it back I am able to do it. But the application is closed and when I open it again none of the data exists. Here is my persistence.xml file <?xml version="1.0" encoding="UTF-8"?> <persistence version="1.0" xmlns="h...

import javax.jdo.PersistenceManager; right approch under gae datastore?

Hello all! Is this the right aproch while using the datastore under Google App Engine? I have this super-class with the right includes: package gae.google.db.object; @PersistenceCapable(identityType = IdentityType.APPLICATION, detachable="true") @Inheritance(strategy = InheritanceStrategy.NEW_TABLE) public class User{ @PrimaryKey...

How to load data with class composition ?

Hi All, Here are my classes : class PriceScale -int ID -float bookingFees -Product product -List<PricePeriod> periods Class Product -int ID -string name -List<PriceScale> priceScales class PricePeriod -DateTime begin -DateTime end -float price -PriceScale scale As you can see I strictly applied business rules "A product as many pri...

Foreign key problem in Java Persistance API with Netbeans 6.9.1

Hi All, I have an error in setting up Java Persistence in Netbeans. I have used MySQL as Back-End Database Server. My Code is as below, Database CREATE TABLE `hub` ( `hub_ID` INT(11) NOT NULL AUTO_INCREMENT, `hub_Name` VARCHAR(45) NOT NULL, PRIMARY KEY (`hub_ID`), UNIQUE INDEX `hub_Name` (`hub_Name`) )ENGINE=MyISAM CREATE TABLE...

Object persistence in .NET and SQL Server, with incomplete values

I am building a form in Net framework 4.0 using linq to sql , and had a question about object persistence. I have a case where a user is asked to fill out a very long form several pages in length. Since it is so long, there is a need to SAVE the data midstream. Session level persistence is not an option, since they could SAVE the form...

Simple and general Client-side Persistence solution?

Hi all: Have to say I wish I could implement server-side persistence (i.e., session-based and/or database-based user state persistence), but unfortunately my uni's server has limited resources provided and it is really hard to implemented a Perl based session solution (CGI::Session and Apache::Session not installed, dated Perl version, ...

Persistence tools in C

I am looking for comfortable mechanisms for storing/restoring dynamically created data on disk. Data is a network of objects, interconnected by indexes or pointers. ...

Add Property to javax.peristence Entity

I right click into the editor of the Entity class. then select Insert Code but do not see the Add Property box. I want to add a birthday property which must be annotated with the javax.persistence.Temporal annotation to mark the property as date field to the underlying database table. I am unsure how to use the Netbeans 6.8 IDE to add ...

How to handle @JoinColumn in your own NamingStrategy implementation?

I thought that joinKeyColumnName() handles @JoinColumn, but in reality I could not get it to work. I want to get rid of the necessity to write name="" in @JoinColumn I want the property to be used as the column name. ...

Spring MVC 3.0: How do I bind to a persistent object

I'm working with Spring MVC and I'd like it to bind a a persistent object from the database, but I cannot figure out how I can set my code to make a call to the DB before binding. For example, I'm trying to update a "BenefitType" object to the database, however, I want it to get the object fromthe database, not create a new one so I do n...

Asking help for many-to-many properties persistence in Hibernate

Hi Buddies, Here I have a question about persist many-to-many properties. Example: class Movie { /** * @hibernate.bag cascade="save-update" table="movie_genre" * @hibernate.collection-key column="ITEM_ID" * @hibernate.collection-many-to-many column="GENRE_ID" class="Genre" * @hibernate.collection-cache usage="r...

JDO Google App Engine validate user

I've been following the google app engine tutorial and the part that explains JDO is done under the basis of a guestbook. So when they query the persistence (BigTable i believe) they are interested in returning all the results. I'm trying to adapt this for showing the results for the specific user but seem to be having trouble with it. ...

Whether to persist or not persist number of results per page. If we want to persist, how to persist.

In our application we are using ASP.NET MVC. On a page we are displaying 10 results per page by default. We want to let the user change this default value of 10 to 20 or 30 or 40. When it is changed, is it good to persist this changed value? To me it looks good to persist the value so that user does not have to change it every time. My ...

Multiple composite ids with relations or single field PKs

I've been dealing with composite id's and asked a few questions and I was recommended to replace my composite PK's with a single id column, and to control integrity with indexes... All of this related to the fact that mapping composite id's isn't that simple... On the other side, some people encourage the usage of composite id's that a...

If I persist a class using hibernate, how do I ensure that the values of some fields are merged while others are created?

Suppose I have a class 'Cheese' with fields type and purchaseDate, such that: public class Cheese{ CheeseType cheeseType; String purchaseDate; public setPurchaseDate(String value){ purchaseDate=value; } public Class CheeseType{ String type; public setType(String value){ type=value; ...

declare a transaction in ejb 3.0

Hi, how can I force the EJB to not flush everything after every single command, I want to do a transaction. I've read that this is done somehow declaratively. But how exactly? @Stateless public class SomeBean{ @PersistenceContext EntityManager em; public void doSomeStuffAndThenFlushToTheDb(){ em.persist(entity); // it's flushed ...

Keeping persistent data in memory

I am about to develop a Windows service in C#. This service needs to keep track of events in the system, and write some data to files from time to time. These ongoing events form a certain state, so I'll keep the state in memory and update it as events will arrive. I don't want to over-complicate things so I don't want the state to be pe...

any sample for batch processing in hibernate ?

Can i find the example of batch processing in java hibernate so that i can run delete queries on two tables. ...

Problem HIbernate + Mysql

I'm having the following problem. I have a survey which indicate the start / end of a given process. When I select the start date, everything works. When I put only the end date (and no other filter the search), here comes the problem. I have a monster delay in the research and the session falls Ext. My bank has about 250,000 registered...

Javascript Object -> SQL, in Javascript

I have a simple client-side Sqlite database (via. Google Gears) I want to use for persistence of the contents of a javascript object's properties (not methods). I don't really care about normalization since it has lots of potentially disparate fields (primitive types, arrays, objects) that would thwart normalization anyway. What would ...