136 | Retrieving JPA Entity Objects of the database. The persistence context serves as a cache of retrieved entity objects. If a requested entity object is not found in the persistence context a new object is constructed and filled with data that is retrieved from the database (or from the L2 cache - if enabled). The new entity object |
133 | Storing JPA Entity ObjectsNew entity objects can be stored in the database either explicitly by invoking the persist method ... an instance of the Employee entity class in the database: Employee employee = new Employee("Samuel ... and changes its state to Managed. The new entity object is stored in the database when the transaction |
129 | Deleting JPA Entity ObjectsExisting entity objects can be deleted from the database either explicitly by invoking the remove ... (); The entity object is physically deleted from the database when the transaction is committed. Embedded objects that are contained in the entity object are also deleted. If the transaction is rolled |
129 | Defining a JPA Entity ClassTo be able to store Point objects in the database using JPA we need to define an entity class. A JPA entity class is a POJO (Plain Old Java Object) class, i.e. an ordinary Java class that is marked ... to serializable classes, which are marked as having the ability to be serialized. The Point Entity |
128 | Updating JPA Entity ObjectsModifying existing entity objects that are stored in the database is based on transparent ... Once an entity object is retrieved from the database (no matter which way) it can simply be modified in memory ... (); The entity object is physically updated in the database when the transaction is committed |
127 | Entity Management SettingsThe <entities> configuration element specifies front end settings that are relevant on the client side and in embedded mode. The default configuration file contains the following <entities> element: <entities> <enhancement agent="true" reflection="warning" /> <cache ref="weak" level2="0mb |
126 | JPA Entity FieldsFields of persistable user defined classes (entity classes, embeddable classes and mapped ... and inverse fields) can be used in both entity classes and embeddable classes. However, the last two groups (primary key and version fields) can only be used in entity classes. Primary key fields |
25 | Step 2: Entity Class and Persistence UnitTo store objects in an ObjectDB database using JPA we need to define an entity class: Open the [New Entity Class] dialog box, e.g. by right clicking the project node (in the [Projects] window) and selecting New > Entity Class... (or New > Other... > Persistence > Entity Class and clicking |
25 | Step 2: Entity Class and Persistence UnitTo store objects in an ObjectDB database using JPA we need to define an entity class: Open the [New Entity Class] dialog box, e.g. by right clicking the project node (in the [Projects] window) and selecting New > Entity Class... (or New > Other... > Persistence > Entity Class and clicking |
24 | Step 2: Entity Class and Persistence UnitTo store objects in an ObjectDB database using JPA we need to define an entity class: Right click ... - use exactly that case sensitive class name. Click Finish to create the new entity class. A new class ... .persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; @Entity |
