About retrieve

tutorial

Step 3: Add a Main Class

Explains how to add the JPA tutorial Main class in Eclipse.... that will store Point objects in the database and then retrieve them from the database: Open the [New Java Class] ... ( ) ) ;   // Retrieve all the Point objects from the database: ...

 
manual

JPA Entity Fields

Explains how to define and use primary keys in JPA, including composite and embedded primary keys. Fields of persistable user defined classes (entity classes, embeddable classes and mapped superclasses) can be classified into the following five groups: Transient fields Persistent fields Inverse (Mapped By ...

 
forum_thread

Transaction isolation support?

I am looking at using ObjectDB for our new project, and its looking good so far. But I have been unable to find any documentation about how transaction isolation is handled. For example: What happens If I am reading data in transaction A, and then transaction B commits while A is reading. (Especially if using LAZY fetch sub object). Do I always just get the list of objects as it looks when the fetch start? Martin   #1 2013-04-14 13:16 I am looking at using ObjectDB for our new project, and its looking good so far. But I have been unable to find a ...

 
release

2.4.0

Release date: 2012-05-20 Download (5.4 MB) Binary:  objectdb-2.4.0.zip You should start by following a  tutorial or reading the manual ...

 
release

2.3.4

Release date: 2011-11-25 Download (5.49 MB) Binary:  objectdb-2.3.4.zip You should start by following a  tutorial or reading the manual ...

 
manual

SELECT clause (JPQL / Criteria API)

Explains how to use the SELECT clause and projections in a JPA/JPQL query. The ability to retrieve managed entity objects is a major advantage of JPQL. For example, the ...

 
forum_thread

Create simple index for a Id field

Hello, I just wanted to write another anotation to my key field so I can have a really simple index. This is the original code: @Entity public class ObjectDbEntity<Key,Value> implements DataItemProvider<Value> {         @Id     private Key key = null;     private Value value = null; and I just want my key to be indexed on my db, just like this: ... a complex task, because you first have to lookup and then retrieve the object, but still too slow in my opinion. Notice I have a db with at least 1M objects, the only way I want to retrieve objects is by the key (or ID). Maybe ObjectDB is not the best ...

 
release

2.3.3

Release date: 2011-11-10 Download (5.49 MB) Binary:  objectdb-2.3.3.zip You should start by following a  tutorial or reading the manual ...

 
forum_thread

Server closes if large query runs out of memory

We are using ObjectDB in production, and have found what we thing to be a serious problem:  the objectdb server can run out of memory and stop if a query deals with too many objects. This isn't the behaviour we expected for a product that we want to use to deliver 24/7 high-volume data collection. ObjectDB surely has some idea of the sizes of objects that it persists and retrieves, and so should be able to fail safely if it finds too many objects being retrieved to fit into memory. There must be some alternative to crashing! #1 2014-08-06 00:27 We are using ObjectDB in production, and have found what we thing to be a serious problem:  the objectdb ser ...

 
forum_thread

OneToMany and cascade delete problem

Hi, I don't really know if this is a bug or maybe model that I make is bad. I have a problem with with two different classes with OneToMany relation to one, shared class. For example (first class): @Entity public static class Store { @OneToMany(targetEntity = Offer.class, mappedBy = "store") private List<Offer> offers; } second class: #1 2011-09-19 16:33 Hi, I don't really know if this is a bug or maybe model that I make is bad. I have a problem with wit ...