About null



Defines the values of the javax.persistence.lock.scope property for pessimistic locking.(Enum of JPA)



Instances of the type EntityType represent entity types.(Interface of JPA)


Foreign key constraint issue

Hi, I'm trying to create two tables (Parent and Child) with a foreign key constraint from Child to Parent so that when the parent is deleted all children are removed as well. Unfortunately, in one specific case that foreign key constraint doesn't apply and I can't figure out what I'm missing. The definitions of the classes are as follows: ... retrieving it first (in which case the list of children is null), both children get deleted. Can you please help me out? ...


Beginners questions

Hello !! I am new in JPA / ObjectDB development and I have many questions: 1. If I understood correctly, ObjectDB is an implementation of JPA standard (currently 2.0)? 1.1. Is ObjectDB on the same level like Hibernate with only difference that Hibernate stores the data in a RDBMS and ObjectDB has its own format?   ... = false ) private EBVerlag verlag = null ; 3.1. Please take a look at column names and tell ...


evalution limit error on digital ocean ubuntu

Trying to run the code on Digital Ocean Ubuntu instance. Generated license and set key in objectdb conf file. It gives below exceeds evaluation error when we try to run the code. Caused by: com.objectdb.o.UserException: Too many persistable types (>10) - exceeds evaluation limit at com.objectdb.o.MSG.d(MSG.java:61) ~[objectdb-2.5.4.jar:na] at com.objectdb.o.MST.UC(MST.java:1090) ~[objectdb-2.5.4.jar:na] at com.objectdb.o.WRA.UC(WRA.java:213) ~[objectdb-2.5.4.jar:na] at com.objectdb.o.TYS.x(TYS.java:768) ~[objectdb-2.5.4.jar:na]... java.lang.NullPointerException: null java.lang.NullPointerException at ...


Insertion Speed Rate and Batch Load

1. I got about 10K inserts / second, is it normal? I would expect more than that, like close to 100K/second. I can definitely do 80K inserts/seconds on Oracle with batch insert on table with one primary key. 2. Is batch update/insert operation supported? I attached the files. ... 80,000  Device instances per second, and with null in the String[] array the rate goes up to 200,000 entity objects per ...



Instances of the type IdentifiableType represent entity or mapped superclass types.(Interface of JPA)


ObectDb 2.3.6 in OSGi environment

Hello, I'm trying to use ObjectDb within OSGi bundles. I have one bundle for db accens which uses ObjectDb and another bundle which includes the POJO models. Everytime I start in plugin evironement i get an PersistenceException, because my POJO not found. If try the same test in normal Java environment everthing works fine. Can you please advice? Thx Peter ... "SELECT rvn FROM RuleValueNode rvn where rvn.parent is null" ) , @ NamedQuery ( name = ...


Empty temporary dat files in the temp folder

Hello, We have questions regarding the pagesX.dat files in the temp directory. We detected a problem on a machine with ‘only’ 2GB free memory on disc drive C:/ because during using our Product the %temp%/objectdb_123... folder growth up to 2GB. And then we run into some following errors due to lack of memory. ... of the first one) empty. Or rather pre filled with null. We observed that the directory is cleaned up sporadic. But for us ...


Object DB vs EclipseLink/TopLink: Unloaded relationships in detached entities

This topic is for those considering migrating from EclipseLink JPA or TopLink to ObjectDB JPA. ... to find that all of my collection relationships were null (not even just empty where appropriate), and on various pages I got NullPointerExceptions where non-null collection results (including non-null empty) were expected. As ...