About table

forum_thread

Join performance in Objectdb

select count(e) from Meta e, ImageNet i, Page p where e.idImage=i.id and e.idPage=p.id; So simple a command cause me half an hour and is running now! Each table has about 160K records. What formula can predict the time for such counting? TIA ... a command cause me half an hour and is running now! Each table has about 160K records. What formula can predict the time for such ...

 
forum_thread

persists and update together ?

hello on mysql i've seen;   INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6) ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);   This query , inserts data or updates if its already available and this will reduce finding same object again. On jpa : User obj2 = ...; ... i've seen;   INSERT INTO TABLE ( a , b , c ) VALUES ( 1 , 2 , ...

 
forum_thread

Help with 'not like/lower' query

Hi again,   Honestly, I'm fairly new with JPA2 Criteria queries - but as far as code effort goes, it has saved me a bit of pain. I'm writing a dynamic query builder (only 1 level deep for basic entities) - but  even though I get most queries to work, I am getting the following error. This is using Criteria with a combination of LOWER/UPPER - NOT LIKE: ... count (with a subsequent fetch of a page of 20 results per table view on the UI) where a user belongs to a company, and the lower case ...

 
api-jdo

Joins.value

The join definitions used for the mapping of this type.(Annotation Element of javax.jdo.annotations.Joins)

 
api-jpa

javax.persistence.Id

Specifies the primary key of an entity.(Annotation of JPA)

 
forum_thread

Is it possible to commit only specific elements?

Hello, As stated above, I would like to know if it is possible to commit only specific elements, or at least update a single table, disregarding the other entities loaded in the persistency context? I have a complex hierarchy of intertwined objects. Currently I am clearing my persistency context, retrieving only the needed ones, creating new ones (which I want to commit), detaching the ones I've previously retrieved and finally committing. My context is big data and performance is an issue.      ... commit only specific elements, or at least update a single table, disregarding the other entities loaded in the persistency context? ...

 
api-jpa

InheritanceType.TABLE_PER_CLASS

A table per concrete entity class.(Enum Constant of javax.persistence.InheritanceType)

 
issue

InternalException during producer/consumer scenario

Hi, I'm trying to use objectdb in a producer/consumer scenario. Producer threads put message objects into a table while consumer threads remove the objects based on age, priority, etc. There are 2 main motivations for using objectdb for this purpose rather than a queue or similar data structure: 1) The consumer can select the "next" object based on a range of potentially complex criteria. 2) The number of objects produced can be potentially exceed available memory so can be held on disk within the objectdb file. ... scenario. Producer threads put message objects into a table while consumer threads remove the objects based on age, priority, etc. ...

 
api-jpa

javax.persistence.ElementCollection

Defines a collection of instances of a basic type or embeddable class.(Annotation of JPA)

 
forum_thread

Failing to read entities under load in multithreaded tests

Hi, We are experiencing an issue in our application that only occurs under load - we sometimes fail to read entities from the database. ... ( strategy = InheritanceType . TABLE_PER_CLASS ) @ TableGenerator ( name = ... ( strategy = GenerationType . TABLE , generator = "TestIdTableGen" ) public long ...