About empty

manual

Collections in JPQL and Criteria Queries

Shows how collections and maps can be used in JPQL queries.... covers the following topics: IS [NOT] EMPTY SIZE [NOT] MEMBER [OF] [NOT] ... Collection Expressions IS [NOT] EMPTY The IS [NOT] EMPTY operator checks whether a specified collection ...

 
forum_thread

InternalError on query of empty database

Hi, I have reasons for sometimes trying to query the database before anything has been created. The problem is the database throws a InternalException when that happens. Is it possible to throw something that identifies that that is the issue, say something like "MissingSchemaException", ie something that clearly shows its because no data of that type has been added? This just makes the exception catching cleaner. Thought thinking about it, it probably needs to be a JPA exception, maybe something like javax.persistence.EntityNotFoundException? ... I'm now getting an empty set returned on empty database. Thanks!!!! edit ...

 
forum_thread

Mapped (Inverse) LAZY @OneToMany vs. Unmapped LAZY @OneToMany

In the code example below (also attached) I would like to understand why I am able to print to console a lazy @OneToMany mapped field after a finding entity manager closes. There is a switch DO_VIEW_BEFORE_CLOSE, and when it is true the fields are accessed and output before the finding entity manager closes and as expected both a mapped @OneToMany list and an unmapped @OneToMany list are viewable: a.listA_mapped:[{A}[4]"ownedElement1", {A}[5]"ownedElement2"] a.listB_unmapped:[{B}[2]"b1", {B}[3]"b2"] ... the mapped list gives null and the unmapped list gives an empty list [], when DO_VIEW_BEFORE_CLOSE = false. ...

 
forum_thread

Memory consumption of empty Strings

After doing some memory related research in my program, I found a possible place for an enhancement of objectdb: My program has several entities which contain many String. Often some of these String are empty (""). To avoid unnecessary memory consumption, the String within the entities are initialized like: String firstName = ""; ... which contain many String. Often some of these String are empty (""). To avoid unnecessary memory consumption, the String within the ... String firstName = ""; In this case every "empty" attribute shares the same String. But after reloading the entities from ...

 
forum_thread

Empty query results after JAR creation

Hi, I struggle with a strange issue. I've embedded ObjectDB in a small application to query cases. Within Netbeans everything works fine but when I create a  JAR File and executed via "Java -Jar xyz.jar", I get either empty results or on some cases a "NoResultException" which appears to report the same issue. I've created a small test case (attached zip file) with sample DB to reproduce the issue.  ... File and executed via "Java -Jar xyz.jar", I get either empty results or on some cases a "NoResultException" which appears to ... 2012-04-24 05:58 Empty results or  NoResultException may be caused by accessing an empty ...

 
forum_thread

Possible issue for JPQL IS EMPTY expression

Possible issue for JPQL IS EMPTY comparison expression: SELECT e FROM MyEntity e WHERE e.collection-valued IS EMPTY throws javax.persistence.PersistenceException: Invalid operand type  for operator IS EMPTY (error 756) Thanks. ... Possible issue for JPQL IS EMPTY comparison expression: SELECT e FROM MyEntity e WHERE e.collection-valued IS EMPTY throws javax.persistence.PersistenceException: Invalid ...

 
forum_thread

LEFT JOIN FETCH over empty embedded collection returns no results

First of all, thank you for promptly implementing JOIN FETCH over nested paths in response to my inquiry a few months ago. However, I have run into one problem: if an embedded collection is empty, but I attempt to LEFT JOIN FETCH all the members of a collection within a (non-existent) member of the first collection, the result of the overall query is an empty set. To use the example from my original post: @Embeddable class A { String val; };   ... I have run into one problem: if an embedded collection is empty, but I attempt to LEFT JOIN FETCH all the members of a collection within ... first collection, the result of the overall query is an empty set. To use the example from my original post: @ ...

 
forum_thread

@ElementCollection Set<Integer> is emptied sometimes

Hi! I'm facing a really strange behavior, which I can't yet reproduce, but it happened 3-4 times already. ObjectDB seems to clear some fields that are @ElementCollection Set<Integer> of my objects. They appear HashSet<Integer> in ObjectDB Explorer. The only common thing I've seen is that this MAY happen when schema changes, even though nothing is changed in that Object's class. Any ideas why would this happen and how could it be avoided? Thanks (version 2.5.3 & Tomee & NetBeans) ... So, my @ElementCollection Set<Integer> fields become empty sometimes during development while schema changes, but not all the times. ... happen anymore, until 1 day ago, when some fields got empty again (but not null). (basically...an empty HashSet<Integer>). ...

 
forum_thread

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. ... dat files they are all (with exception of the first one) empty. Or rather pre filled with null. We observed that the directory ...

 
forum_thread

Handling a case of searching an empty database

Hi, I have posted a question on Stack Overflow but there is limited support for ObjectDB on there, so I will post it here. It is a lot clearer on the page, if this is a problem though I can copy it to a post here.   Thanks in advance. #1 2013-12-23 23:53 Hi, I have posted a question on Stack Overflow but there is limited support for ObjectDB on there, so I will post ...