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Forum
29

Uninitialized primary key (id = 0)

Exception in thread "main" [ObjectDB 2.2.9_04] javax.persistence.RollbackException Failed to commit transaction: Attempt to reuse an existing primary key value (image.Meta:0) (error 613) at com.objectdb.jpa.EMImpl.commit(EMImpl.java:277) I check the db by explorer.jar, and find
Forum
27

Internal ObjectDB error by read the primary key

Internal ObjectDB error by read the primary key
Manual
25

Database Explorer

and primary key separated by # (e.g. Point#1). A collection can be specified as a comma separated list ... , which has to be specified by type and primary key separated by # (e.g. Point#1). The Edit > Set Reference ... type and primary key separated by # (e.g. Point#1). The Edit > Add to Collection > Add New Object
FAQ
25

Is ObjectDB better than competing object databases?

databases do not support user defined primary keys, even though this is very useful in almost every application. ObjectDB supports user defined primary keys including composite primary keys. The support
JDO Doc
22

javax.jdo.annotations.Key

javax.jdo.annotations Annotation Key Target: Fields (including property get methods) Annotation for the key of a map relation. Corresponds to the xml element "key". Since: JDO 2.1 String column Name of the column to store the key in. Name of the column to store the key in. Returns: name
JPA Doc
21

javax.persistence.EntityManager

(Class entityClass, Object primaryKey) Find by primary key. Find by primary key. Search for an entity of the specified class and primary key. If the entity instance is contained in the persistence context, it is returned from there. Parameters: entityClass - entity class primaryKey - primary key
JPA Doc
20

JPA Annotations for Classes

are useful in representing composite primary keys as explained in the Primary Key section of the ObjectDB manual.
JPA Doc
20

JPA Annotations for Value Generation

Automatically generated values are mainly useful for primary key fields, but are supported by ObjectDB also for regular (non primary key) persistent fields. At the field level, the @GeneratedValue with an optional GenerationType strategy is specified: The @GeneratedValue annotation
Manual
20

ORDER BY clause (JPQL / Criteria API)

. The following query returns Country objects ordered by currency as the primary sort key and by name as the secondary sort key: SELECT c.currency, c.name FROM Country c ORDER BY c.currency, c.name ... this case, the first expression is the primary order expression. Any additional order expression
Manual
20

Database Management Settings

Explains settings and performance tuning of the ObjectDB Java object database for JPA/JDO.