About unique

forum_thread

Using multiple databases

Is it possible for an ObjectDB PersistenceManger/EntityManager to connect to more than one database at a time? Also, can objects in one database reference objects in another database (e.g. through globally unique identifiers)? ... objects in another database (e.g. through globally unique identifiers)? edit ...

 
faq

Is ObjectDB a NoSQL Database?

ObjectDB is a unique NoSQL database. It doesn't have the known disadvantages and ...

 
manual

Retrieving JPA Entity Objects

Explains how to use JPA to retrieve entity objects from the database. The Java Persistence API (JPA) provides various ways to retrieve objects from the database. The retrieval of objects does not require an active transaction because it does not change the content of the database. The persistence context se ...

 
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 = ""; ... from objectdb, every empty String has become a new (unique) String object, which is a waste of memory (refer to ...

 
page

What is the Java Persistence API (JPA)?

... standard JPA you can keep your application portable. The unique benefit of using ObjectDB is that the overhead of an intermediate ORM ...

 
forum_thread

String Contains Query Result - Possible?

Hi, I have a managed database for an Entity, "Program", filled with String fields, "description", that are effectively unique sub-strings of a system generated description. Example: System: For Series Sales usage: 6014-Private Individual Swim Lessons  10-Pack Database: 6014-Private Individual Swim Lessons  10-Pack I would like to know if it is possible to have a query return the "Program" object using the System Description? I've considered doing something similar to... ... a String field, "description", that is effectively a unique sub-string of a system generated description. Example: ...

 
api-jpa

SecondaryTable.uniqueConstraints

(Optional) Unique constraints that are to be placed on the table.(Annotation Element of javax.persistence.SecondaryTable)

 
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. ... to read them from the DB with "No matching results for a unique query" error. The error occurs in 2-3% of iterations. When I run ...

 
api-jpa

CollectionTable.uniqueConstraints

(Optional) Unique constraints that are to be placed on the table.(Annotation Element of javax.persistence.CollectionTable)

 
api-jdo

addSubquery(sub, variableDeclaration, candidateCollectionExpression, parameters)

Add a subquery to this query.(Method of javax.jdo.Query)