hibernate

Can Hibernate default a Null String to Empty String

In our application we are pulling data from a DB2 mainframe database. If the database has "low values" in a field, hibernate sends a "null" value in the object. This occurs even if the column is defined as "not null". As we are doing XML parsing on this, Castor is having trouble with it. I would like to fix this in Hibernate. Also, ...

Transaction Management

Hi all, In my code I am updating two table, one after the other. update(table1_details); update(table2_details); So if the update fails in table1 , table2 should not be updated or should be rolled back. How to handle this situation. I know I have to use transaction. Can some one help with code !!! I am using Java with spring and hi...

Hibernate 3.5.0 causes extreme performance problems

I've recently updated from hibernate 3.3.1.GA to hibernate 3.5.0 and I'm having a lot of performance issues. As a test, I added around 8000 entities to my DB (which in turn cause other entities to be saved). These entities are saved in batches of 20 so that the transactions aren't too large for performance reasons. When using hibernate ...

Hibernate collection multiple types

I have a class Player that contains a list of Accessory objects. There are two kinds of Accessories. SocketedAccessories have a list of SocketJewels, and MagicAccessories have a list of MagicEnchantments. At the database level, there is a players table that represents the player, and an accessories table that contains a list of access...

Are Hibernate named HQL queries (in annotations) optimised?

A new colleague has just suggested using named HQL queries in Hibernate with annotations (i.e. @NamedQuery) instead of embedding HQL in our XxxxRepository classes. What I'd like to know is whether using the annotation provides any advantage except for centralising quueries? In particular, is there some performances gain, for instance ...

Is it a good idea to close and open hibernate sessions frequently?

Hi, I'm developing an application which requires that state of entities be read from a database at frequent intervals or triggers. However, once hibernate reads the state, it doesn't re-read it unless I explicitly close the session and read the entity in a new session. Is it a good idea to open a session everytime I want to read the en...

Hibernate Hql find result size for paginator

Hi, I need to add paginator for my Hibernate application. I applied it to some of my database operations which I perform using Criteria by setting Projection.count().This is working fine. But when I use hql to query, I can't seem to get and efficient method to get the result count. If I do query.list().size() it takes lot of time and I t...

DataSource for Tomcat web app, Spring and Hibernate

Web app runs on Tomcat. Datasource is configured with Spring configuration, and is used by Hibernate. If we cannot use JNDI, what would you suggest to use as a DataSource? org.springframework.jdbc.datasource.DriverManagerDataSource will be ok? It's not very good, but sincerely speaking, it can be used on production server, right? Just ...

How to use Hibernate SchemaUpdate class with a JPA persistence.xml?

I've a main method using SchemaUpdate to display at the console what tables to alter/create and it works fine in my Hibernate project: public static void main(String[] args) throws IOException { //first we prepare the configuration Properties hibProps = new Properties(); hibProps.load(Thread.currentThread().getContextClassLoader(...

Hibernate sequence should only generate when ID is <=0

Hi all, I'm using the folowing sequence in my code. (I got the sequence and @Id @SequenceGenerator(name = "S912_PRO_SEQ", sequenceName = "S912_PRO_SEQ", allocationSize = 1) @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "S912_PRO_SEQ") @Column(name = "PRO_ID", unique = true, nullable...

Implementing EAV pattern with Hibernate for User -> Settings relationship

I'm trying to setup a simple EAV pattern in my web app using Java/Spring MVC and Hibernate. I can't seem to figure out the magic behind the hibernate XML setup for this scenario. My database table "SETUP" has three columns: user_id (FK) setup_item setup_value The database composite key is made up of user_id | setup_item Here's the...

Can I reuse a column across subclasses in a Hibernate table-per-hierarchy inheritance strategy?

In a simple inheritance tree, an abstract superclass has two subclasses. The subclasses both store a key-value pair, but but one will be holding a type Encrypted String, and the other one a plain old String. Now, my question is can I do this: @Entity @Inheritance(strategy = InheritanceType.SINGLE_TABLE) public abstract Attribute { ...

JDBC connection for a background thread being closed accessing in Websphere

Hi, I have an application running in Websphere Portal Server inside of Websphere Application Server 6.0 (WAS). In this application for one particular functionality that takes a long time to complete, I am firing a new thread that performs this action. This new thread opens a new Session from Hibernate and starts performing DB transactio...

Configure Hibernate to obtain a fresh connection from a connection pool.

How do I configure Hibernate so that each time I call sessionFactory.openSession() it connects with a new connection from the connection pool? The connection pool is managed by Websphere Application Server and is a JDBC Data Source. Thanks ...

hibernate insert to a collection causes a delete then all the items in the collection to be inserted again

I have a many to may relationship CohortGroup and Employee. Any time I insert an Employee into the CohortGroup hibernate deletes the group from the resolution table and inserts all the members again, plus the new one. Why not just add the new one? The annotation in the Group: @ManyToMany(cascade = { PERSIST, MERGE, REFRESH }) @JoinTab...

What does transaction.commit() do when the flushmode is set manual in Hibernate?

Here is a block of code in the Java Persistence with Hibernate book by Christian and Gavin, Session session = getSessionFactory().openSession(); session.setFlushMode(FlushMode.MANUAL); // First step in the conversation session.beginTransaction(); Item item = (Item) session.get(Item.class, new Long(123) ); session.getTransaction()....

How to properly test Hibernate length restriction?

I have a POJO mapped with Hibernate for persistence. In my mapping I specify the following: <class name="ExpertiseArea"> <id name="id" type="string"> <generator class="assigned" /> </id> <version name="version" column="VERSION" unsaved-value="null" /> <property name="name" type="string" unique="true" not-null="tr...

Hibernate won't autogenerate sequence table

I'm trying to use a sequence table to generate keys for my entities. I notice that if I just use the @GeneratedValue(strategy=GenerationType.TABLE) with no explicit generator, Hibernate will automatically create the hibernate_sequences table in my DB if it doesn't exist. This is great. However, I wanted to make some changes to the seq...

Mapping Hashmap of Coordinates in Hibernate with Annotation

I've just started using hibernate and I'm trying to map walking distance between two coordinates into a hashmap, There can be many connections from one "FromCoordinate" to another "ToCoordinate". I'm not sure if i've implemented this correctly, What annotations do i need to map this MashMap? Thanks HashMap> coordWalkingConnections = new...

Why so Long time span in creating Session Factory?

Hi My project is web application running in the tomcat container. This application is a spring framework based hibernate application. The problem with this is it takes a lot of time when creates session factory. here is the logs 2010-04-15 23:05:28,053 DEBUG [SessionFactoryImpl] Session factory constructed with filter configurations :...