About JOIN

forum_thread

Error 613 - i cant put a list<Athlete> into a Squad object

hey guys Im a swiss student and my english is not that good and ive never posted in your forum, so thats why im sorry if im doing any mistakes, but i have big trouble, because ive to get this straight till end of week. i uploaded also all classes but if u see the problem in the main problem field the classes are copied after the problem description. the structure: #1 2011-04-04 17:38 hey guys Im a swiss student and my english is not that good and ive never posted in your forum, so thats ...

 
issue

Database File Compression

ObjectDB database files are usually smaller than database files of other Database Management Systems (object and Relational) but still, an additional internal compression is possible. Usually smaller files are also faster because less I/O operations are required and memory cache can be used more efficiently. But compression and decompression consumes CPU time. Therefore, the effect of compression on Object databases is currently unknown. Feature Request Version: Priority: Normal Status: Active Replies: 0 Type:  Feature Request ...

 
issue

Embedded Database Replication

As we all know, embedded databases out perform server databases on every occasion. The problem with embedded databases is that theyre difficult to scale. If I were to create an entire enterprise web application within a single jar file using embedded tomcat and embedded objectdb I would run into problems trying to cluster the data. It would be really useful if some kind of new external replicator application was created that can be used by server administrators to ensure replication is optimal and healthy. Feature Request Version: 2.6.1 Priority: Normal Status: Active Replies: 0 Type:  Feature Request ...

 
forum_thread

New Web Application Tutorials

New ObjectDB/JPA tutorials have been published today: Eclipse/JPA Web Application Tutorial NetBeans/JPA Web Application Tutorial The new tutorials demonstrate how to build a simple database driven web application using ObjectDB and JPA. Understanding these tutorials requires some familiarity with basic concepts and principles of Java web applications, including Servlets, JSP and HTML. #1 2010-06-07 10:12 New ObjectDB/JPA tutorials have been published today: Eclipse/JPA Web Application Tutorial NetBeans ...

 
api-jpa

getModel()

Return the metamodel representation for the set attribute.(Method of javax.persistence.criteria.SetJoin)

 
issue

Email notification about new build

Just a quick thought. It would be nice to get email notification about new builds. If a new build resolves a problem that I'm not subscribed for, I don't know about it until i check ODB page :) Website Version: 2.4.4 Priority: Normal Status: Active Replies: 0 Type:  Website ...

 
api-jdo

Join.generateForeignKey

Generate or assume a foreign key constraint exists on the column or columns associated with this join.(Annotation Element of javax.jdo.annotations.Join)

 
api-jpa

SecondaryTable.pkJoinColumns

(Optional) The columns that are used to join with the primary table.(Annotation Element of javax.persistence.SecondaryTable)

 
issue

Explorer Features - refresh + viewing open embedded database

Request for feature: Ability to auto-refresh an explorer view, say at regular intervals of a few seconds. (at a minimum one ought to be able to manually refresh, for example the list of persistent types). additionally, it would be useful to be able to view an embedded database (read only mode) via the explorer. Feature Request Version: 2.2.2 Priority: High Status: Active Replies: 0 Type:  Feature Request ...

 
manual

[ODB1] Chapter 7 - JDOQL Queries

Explains how to use JDOQL, the Java/JDO Query Language.... Unbound variables, which serve as a replacement for the JOIN operation of SQL Support of bound variables is mandatory, but ... by JDO. Queries with unbound variables are similar to JOIN queries in SQL because every combination of variables has to be checked ...