About SECOND

forum_thread

Performance question

Hello, suppose you have an entity that holds a reference to another entity which in turn contains e.g. a date field you want to query for. Is there an improvement in performance if I create a "mirror" date field in the original entity, removing the need to traverse through the referenced other entity? So, querying for "all objects with object.otherobject.date > 1.1.1980" is slower than "all objects with object.date > 1.1.1980"? Or doesn't this matter, using proper indexing? Thanks, Benjamin ... improvement. If you keep the date only in the second entity class - at least define 2 indexes: one on the date field and the ...

 
forum_thread

Optimization Question

One of our uses for your ObjectDB software is in maintaining the current state of a large number of data objects called tracks. These tracks change very frequently over time (every 10-15 seconds is not unreasonable), but they are also very large complex data structures so it's extremely difficult to identify exactly what fields have changed from one update to the next. Currently the following sequence executes when a track update comes in: - If it’s a new track simply add it to the database. #1 2010-06-16 15:41 One of our uses for your ObjectDB software is in maintaining the current state of a large number of data objects cal ...

 
forum_thread

Problem with @OrderBy

When I use @OrderBy and supply multiple order fields I get and error when ObjectDB loads that entity. Example code: @Entity @Table(name="Problems", schema = myDB") public class Defects  implements Serializable { ... ...  @OneToMany(mappedBy="problem") @OrderBy("seqRel, noteSeq") Set<Notes> notes; ... ... } ... The error seems to be the second field "noteSeq" in the above example is referenced as if it were an ...

 
issue

Typo in ObjectDB 1.0 Manual

Support > Knowledge Base > ObjectDB 1.0 Manual > Chapter 7 "JDOQL Queries" > Section 7.2 "Query Filter Syntax" > Subsection "Fields" > Second to last sentence Remove "not" from that sentence.   "An attempt to access a field or invoke a method using a null reference results in a false evaluation for the containing expression but no exception is not thrown."   ... 7.2 "Query Filter Syntax" > Subsection "Fields" > Second to last sentence Remove "not" from that sentence. ...

 
forum_thread

100% CPU when using multiple BETWEEN

Hi, we are evaluating ObjectDB 2.5.1_03 in embedded mode. We have a DB of about 2800 instances of a class that has two java.lang.String members: toExtension and fromExtension. There are other members in the class, but not relevant to the problem.   A query like this cause the java process to start running at 100% CPU (endless loop) and it never recovers: ...   The following query works fine (sub second response): SELECT r FROM RecordingMetaData AS r ...

 
forum_thread

Evaluation license in a different network

Dear Support Team I recognized, that the evaluation license is bounded to the LAN network in my office and didn't work in a different (WLAN) network. Is there any problem if I create a second license key for my home office (i.e. WLAN). best regards Arne ... (WLAN) network. Is there any problem if I create a second license key for my home office (i.e. WLAN). best regards ...

 
forum_thread

@OneToOne query issue with OR and IS NULL

Hello, I'm struggeling to get a query run right. I have 2 entities (simplified) ... In the first one, the member "another" is null... in the second one "another" is set. Now I want to query " select from A ...

 
forum_thread

calling persist on an object more than once

results in an error (613) when the transaction is commited: [ObjectDB 2.2.4] javax.persistence.RollbackException Failed to commit transaction: Attempt to reuse an existing primary key value (common.model.UserSession:13) (error 613) at com.objectdb.jpa.EMImpl.commit(EMImpl.java:271) at javax.jdo.Transaction$commit.call(Unknown Source)   I submit that there are a number of problems with this: a) the error message is not helpful ... on object xxxx'), and b) to throw the exception at the second persist, rather than waiting for commit. Thoughts? ...

 
api-jpa

lessThan(x, y)

Create a predicate for testing whether the first argument is less than the second.(Method of javax.persistence.criteria.CriteriaBuilder)

 
api-jpa

setHint(hintName, value)

Set a query property or hint.(Method of javax.persistence.TypedQuery)