11 | Index Definition. When an entity object is stored in the database every indexed field must contain either null or ... to values that are stored as part of the entity. Therefore, indexes on multi part paths are only allowed when using embeddable classes as fields of embedded object are stored as part of the containing |
9 | Chapter 2 - JPA Entity ClassesJPA Entity classes are user defined classes whose instances can be stored in a database. To store data in an ObjectDB database using JPA you have to define entity classes that represent your application data object model. This chapter explains how to define and use entity classes. |
9 | What is ObjectDB?ObjectDB is an Object Oriented Database Management System (ODBMS). It provides all the standard database management services (storage and retrieval, transactions, lock management, query processing, etc.), but it uses an object oriented model to store and manage data. You can easily store ordinary |
9 | Updating JPA Entity ObjectsModifying existing entity objects that are stored in the database is based on transparent persistence, which means that changes are detected and handled automatically. Transparent Update ... can be cascaded from all the entity objects that have to be stored in the database, including from |
2 | Step 3: Add a Main ClassIn this step we will add a main class to the project to store and retrieve Point objects from ... .createEntityManager(); // Store 1000 Point objects in the database: em.getTransaction().begin ... .close(); emf.close(); } } The main method creates an ObjectDB database file, stores |
1 | Step 4: Add a Servlet Class Guest entity object is constructed and stored in the database. All the Guest entity objects are retrieved from the database and stored in the request's "guest" attribute. Then the processing |
1 | Step 3: Define an EJB Session Bean em; // Stores a new guest: public void persist(Guest guest) { em.persist(guest ... two methods: persist - for storing a new Guest entity object in the database. getAllGuests |
1 | Step 2: Define a JPA Entity ClassTo store objects in an ObjectDB database using JPA we need to define an entity class: Open the [New Java Class] dialog box, e.g. by right clicking the tutorial package node (in the [Projects] window ... class that stores and retrieves instances of the Point entity class. |
1 | Step 2: Define a JPA Entity ClassTo store objects in an ObjectDB database using JPA we need to define an entity class: Right click on the project in the [Package Explorer] window and select New > Class. Enter tutorial as the package ... that stores and retrieves instances of the Point entity class. |
1 | [ODB1] Chapter 5 - JDO Connections storing, retrieving, updating and deleting database objects, are provided in the next chapter (Chapter ... transactions on a database. In JDO, operations that affect the content of the database (store, update ... are applied to the database is not acceptable. Before commit() starts writing to the database it stores |
