About Object Database

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Manual
17

GROUP BY and HAVING clauses

clause. When a GROUP BY clause exists in a JPQL query, database objects (or tuples of database objects ... over all the Country objects in the database. The GROUP BY clause groups these Country objects by ... properties of generated groups instead of individual objects and fields. The position of a GROUP BY
Manual
17

JPA Query Structure (JPQL / Criteria)

rather than just field values from database tables, as with SQL. That makes JPQL more object oriented friendly ... JPQL Query The following query retrieves all the Country objects in the database: SELECT c FROM ... over objects in the database. A query variable that is bound to an entity class is referred to as
Manual
17

Paths and Types in JPQL and Criteria API

over all the Country objects in the database. For a country with no capital city, such as Nauru, c.capital ... of all the entity objects in the database, excluding Country entity objects: SELECT COUNT(e) FROM ... is an extension of ObjectDB that can be used to iterate over all the entity objects in the database
Manual
16

JPA Lifecycle Events

(added to the EntityManager). @PostPersist - after storing a new entity in the database (during commit or flush). @PostLoad - after an entity has been retrieved from the database. @PreUpdate ... the database (during commit or flush). @PreRemove - when an entity is marked for removal in
JDO Doc
16

Constants.OPTION_MAPPING_HETEROGENEOUS_OBJECT_TYPE

Static Field javax.jdo.Constants String OPTION_MAPPING_HETEROGENEOUS_OBJECT_TYPE "javax.jdo.option.mapping.HeterogeneousObjectType" Since: JDO 2.1 See Also: PersistenceManagerFactory.supportedOptions()
Forum
15

Best practice: Database update/migration of embedded databases in products

is now held otherwise. The product store user data in the ObjectDB-Database. Example: V1.0: EntityPerson ... city;}     DB3: [name=”Max Mustermann”; zip=”26135”; city=”Oldenburg”] How can we load the Database ... -> V2.0 directly, and you make sure that on upgrade all the old objects are converted and stored in
FAQ
14

Which API should I use - JPA or JDO?

code. When to prefer JDO JDO might be preferred when portability to other object databases is more important than general portability to both object and relational databases. JPA is designated to be used mainly with relational databases. ObjectDB is the only object database that supports JPA
Manual
14

Setting and Tuning of JPA Queries

since the setter methods in Query and TypedQuery support method chaining (by returning the query object on which they were invoked). Flush Mode (setFlushMode) Changes made to a database using an EntityManager ... . Therefore, before a query is executed, uncommitted database changes (if any) have to be flushed to the database in
Manual
14

WHERE clause (JPQL / Criteria API)

JPQL query that retrieves selective objects from the database. Out of the four optional clauses ... of this query defines an iteration over all the Country objects in the database using the c range ... the WHERE predicate. For entity classes with millions of objects in the database there is a huge
Tutorial
14

Step 3: Add a Main Class

"); EntityManager em = emf.createEntityManager(); // Store 1000 Point objects in the database ... (); // Find the number of Point objects in the database: Query q1 = em.createQuery("SELECT ... all the Point objects from the database: TypedQuery query = em.createQuery