87 | Embedded Object inside another embedded object - is that possible?I have an entity with an embedded object - it works fine. Now I am trying to add an embedded object inside the first level embedded object - but it does not seem to store it and does not throw either... I was wondering if it was a limitation or not? has anyone tried this before? Thanks EKK Emmanuel |
19 | Database Explorer objects. The [Schema] window shows the user defined persistable types (entity and embeddable classes) in ... the approach of traditional visual database tools. Every row in the table represents a single object ... a single database object. This type of viewer is useful for viewing data of a simple object model. In |
19 | SELECT clause (JPQL / Criteria API)The ability to retrieve managed entity objects is a major advantage of JPQL. For example, the following query returns Country objects that become managed by the EntityManager em: TypedQuery ... > results = query.getResultList(); Because the results are managed entity objects they have all the support |
16 | CRUD Database Operations with JPAGiven an EntityManager, em, that represents a JPA connection to the object database, we can use it to store, retrieve, update and delete database objects. Storing New Entity Objects The following code fragment stores 1,000 Point objects in the database: em.getTransaction().begin(); for (int |
15 | Locking in JPA in ObjectDB (and in JPA) is always at the database object level, i.e. each database object is locked separately. Optimistic locking is applied on transaction commit. Any database object ... is being performed on an old version of a database object, for which another update has already been committed |
15 | JPA Primary KeyEvery entity object that is stored in the database has a primary key. Once assigned, the primary key cannot be modified. It represents the entity object as long as it exists in the database. As an object database, ObjectDB supports implicit object IDs, so an explicitly defined primary key is not |
1 | [ODB1] Chapter 7 - JDOQL QueriesThere are various ways to retrieve objects from an ObjectDB database, as shown in section 6.3 ... for RDBMS. It provides object retrieval from the database according to a specified selectioPlan ... : A candidate collection containing persistent objects (usually an Extent) A candidate class (usually |
1 | [ODB1] Chapter 4 - JDO Metadata in the JDO specification, are ignored by ObjectDB if specified (as a pure object database, ObjectDB always uses datastore identity with its own object-id class). 4.3 Metadata for Fields Unlike ... and persistent in JDO), or a field whose declared type is java.lang.Object or some interface |
1 | [ODB1] Chapter 5 - JDO Connections storing, retrieving, updating and deleting database objects, are provided in the next chapter (Chapter ... your application JDO portable these objects are accessed through the standard JDO interfaces. Obtaining ... PersistenceManager instance, in any context, to return its associate Transaction object. The strong |
1 | [ODB1] Chapter 3 - Persistent Classes. Instances of these classes that represent objects in the database are called persistent objects or persistent instances. Objects that do not represent anything in the database (including instances of persistent classes that live only in memory) are called transient objects or transient instances |
