ObjectDB ObjectDB

Internal Website Search

41-50 of 200 resultsRefresh

JPA Primary Key

. Reference to an entity object. Composite Primary Key A composite primary key consists of multiple ... ; : } When an entity has multiple primary key fields, JPA requires defining a special ID class

Setting and Tuning of JPA Queries

uses automatic optimistic locking to prevent concurrent changes to entity objects by multiple users

Database Replication and Clustering

ObjectDB supports master-slave replication (cluster). When replication (or clustering) is used, the same database is managed on multiple machines (nodes), possibly in different geographic locations. This could help in achieving high availability, fault tolerance and prompt disaster recovery. In

JPA Query Expressions (JPQL / Criteria)

: * (multiplication), / (division), + (addition) and - (subtraction). Comparison operators

Retrieving JPA Entity Objects

that field (multiple entity objects can be referenced by a collection field): @Entity class Employee

JPA Named Queries

", query="SELECT c FROM Country c") public class Country { ... } Attaching multiple named


multiple variables and JOIN, and cannot include the GROUP BY, HAVING and ORDER BY clauses

WHERE clause (JPQL / Criteria API)

)); Multiple Restrictions The second where method takes a variable number of arguments of Predicate type

CRUD Database Operations with JPA

the result objects. It should be used (rather than getSingleResult) when multiple results

[ODB1] Chapter 4 - JDO Metadata

X.jdo must be dedicated to a single class whose name is X. Metadata for multiple classes ... and cannot be shared by references from multiple objects. In addition, embedded objects of persistent classes

Getting Started

ObjectDB is very easy to use. Follow the Getting Started Tutorial and the Quick Tour manual chapter and in minutes you may be able to write and run first Java programs against ObjectDB.

Prior knowledge or experience in database programming (SQL, JDBC, ORM, JPA, etc.) is not required, but some background in using the Java language is essential.

Need Help?

  1. Search ObjectDB website
  2. Read the FAQ
  3. Follow the Tutorials
  4. View or post in the forum
  5. Search or file an issue
  6. Contact support