About primary key

forum_thread

JPA and handling large data sets

This is not a rellay ObjectDB problem, rather a JPA problem. Our web-based DB supports Hibernate or JPA (ElicpseLink/ObjectDB). We implemented a export/import class to export the whole database or single datasets (domains) in a persistence layer/database independent format. This class works fine - DB exports form a Hibernate/MySQL base via the independent formt to ObjectDB is possible. But exporting large binary data sets is very slow. To avoid memory problems the binary data type is read step by step during the export with the  query/setFirstResult() & setMaxResults().... For example, if your query returns results ordered by the primary key, use the value of the primary key of the last object in one batch as a ...

 
api-jpa

javax.persistence.Column

Is used to specify the mapped column for a persistent property or field.(Annotation of JPA)

 
api-jpa

SecondaryTable.pkJoinColumns

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

 
issue

InternalException

I'm getting a new InternalException (see below). No repeatable example as yet but will work on that and let you know as soon as we have one. If there's anything in the exception which could help us narrow down the problem please let me know. ... detached object that causes the exception has no id (primary key) fields. ObjectDB supports automatic ids (when no id fields are defined) ...

 
issue

again merger missing logs + objectdb exception

we are facing similar problems as we had before, in the log we have a lot of entries merger ... missing + an objectdb exception. Some objects in the system behave strange. This is a part of the log: ... [2017-09-26 12:16:14 #1222 store] SectionClassifier: SectionClassifier{238146996->merger[3309]-missing:1} [2017-09-26 12:16:25 #1223 store] SectionClassifier: SectionClassifier{238146996->merger[3309]-missing:1} ... section is stored in a separate page and has a wrapper key that consists of the original primary key of the object with additional information about the section (e.g. ...

 
release

2.2.0

... Fixed a bug in handling JOIN queries with primary key fields. Version 2.0.4 Added support for JTA and ...

 
manual

Index Definition

Describes how to define indexes in JPA entity classes and explains how indexes are used in JPQL queries.... have the same value in a unique field (similar to how primary keys behave). @Index javax.jdo.annotations.Index ... be defined on ordinary persistent fields (not on primary key / version fields). Composite Index A composite index is an index on ...

 
release

2.1.1

... Fixed a bug in handling JOIN queries with primary key fields. Version 2.0.4 Added support for JTA and ...

 
release

2.2.5

... locking bug . Fixed a bug in using primary key fields in queries. Fixed a bug in queries on deleted ...

 
api-jpa

javax.persistence.OrderBy

Specifies the ordering of the elements of a collection valued association or element collection at the point when the association or collection is retrieved.(Annotation of JPA)