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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 ... _context">persistence context serves as a cache of retrieved entity objects. If a requested entity

Entity objects are in-memory instances of entity classes (persistable user defined classes), which can represent physical objects in the database. Managing an ObjectDB Object Database using JPA requires using entity objects

New entity objects can be stored in the database either explicitly by invoking the Object">persist method or implicitly as ... _Object">persist(employee); em.

Detached entity objects are objects in a special object_life_cycle">state in which they are not managed by any EntityManager but still represent objects in the database. Compared

Existing entity objects can be deleted from the database either explicitly by invoking the Object">remove method or implicitly ... In order to delete an object from the database it has to first be retrieved (no matter

, grouping queries and aggregate queries) which are usually missing from Object Oriented Databases are also supported by ObjectDB. The combination of Object Database features with Relational Database features ... >Up to 2,147,483,648 indices per database file. Up to 9,223,372,036,854,775,808 entity objects

Modifying existing entity objects that are stored in the database is based ... > Transparent Update Once an entity object is retrieved from ... /find_Class__Object">find(Employee.class, 1); em.

a relational database management system (RDBMS) to store and retrieve Java objects requires slow conversions between graphs of Java objects and flat database table rows. Object Relational Mapping (ORM ... , and even add their own overhead. ObjectDB supports direct storage of graphs of objects

. However, you should consider the following points when doing your own objective comparison of object ... . It is the only object database with built in support for the Java Persistence API (JPA). It also supports a more recent and advanced version of the Java Data Objects (JDO) API than competing object databases.

This chapter describes how to use ObjectDB to manage database objects. 6.1  Making Objects Persistent In JDO applications, every object in memory is either a persistent object, i.e