About table


Report Generation with BIRT and JPA

Demonstrates how to use ObjectDB as a data source of the Business Intelligence and Reporting Tools (BIRT), open source report generator.... will be presented in the BIRT report using a chart and a table: The tutorial consists of the following steps:  ... a BIRT Report Chart Step 6: Design a BIRT Report Table ...


Removing entity class

Hello, I am using evaluation version of ObjectDB for long term private project. Recently I hit the 10 entities limit and got exception: com.objectdb.o.UserException: Too many persistable types (>10) - exceeds evaluation limit Among the 10 entities in the project there are 2 entities I added long time ago and they were never really used. I deleted them from Java source code, but there are still in ObjectDB database. The 2 tables for these entities are empty, but the tables exist, so they count into 10 entities limit. ... My question is: Is it possible to remove entity/table completely from ObjectDB database, in order to make space for new ...


Comparison in JPQL and Criteria API

Explains how comparison operators can be used in JPQL queries, including in comparing null values.... sets of comparison operators, as shown in the following table:   Set 1 ... Comparing NULL values The following table shows how NULL values are handled by each comparison operator. One ...



Specifies the version field or property of an entity class that serves as its optimistic lock value.(Annotation of JPA)



Annotation for a column in the database.(Annotation of JDO)



This value defines the default behavior for pessimistic locking.(Enum Constant of javax.persistence.PessimisticLockScope)



In addition to the behavior for PessimisticLockScope.NORMAL, element collections and relationships owned by the entity that are contained in join tables will be locked if the javax.persistence.lock.scope property is specified with a value of PessimisticLockScope.EXTENDED.(Enum Constant of javax.persistence.PessimisticLockScope)



(Optional) The primary key value in the generator table that distinguishes this set of generated values from others that may be stored in the table.(Annotation Element of javax.persistence.TableGenerator)


Persist error @ManyToMany how to define correct entities relationships

I have Product entities containing a list of Category enties. Each product can have multiple Category but all sue the same limited set of Category entities. There is not changes made to Category from Product. The category ID is taken from the webservice Object ID (unique too). ... to be able to persist the 1000 products and keep Catgory table at 20 entities, not 1000 or 2000.   ... kinda works except now no category entity is created, the table is empty, however categories are well present within Product (as if they ...


Dirty checking

Hi, wondering if anyone knows the best way to detect which objects have been changed in the database. ie: which objects, and which collections of objects, have been dirtied.     ... String username } Now assume a single html table, showing a list of users with these columns: Company name, User name So, first the client loads the user table. The actual users rows may depend on whether the client is an ...