About primary key

21-30 of 200Refresh
Forum
32

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
30

Internal ObjectDB error by read the primary key

Internal ObjectDB error by read the primary key
Manual
29

Database Explorer

and primary key separated by # (e.g. Point#1). A collection can be specified as a comma separated list ... to set a reference to an existing entity object, which has to be specified by type and primary key ... to an existing entity object, which has to be specified by type and primary key separated by # (e.g
FAQ
29

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
26

javax.jdo.JDOEntityManager

) Find by primary key. Find by primary key. Search for an entity of the specified class and primary key ... there. Parameters: entityClass - entity class primaryKey - primary key Returns: the found entity instance or null ... an entity type or the second argument is is not a valid type for that entity’s primary key or
JDO Doc
24

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
24

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
Forum
24

Inserted entities with strings as keys and indices needs more and more ram memory in comparing to primitive integers as keys and indices

Hello, I have a problem with inserting of many entities. We use strings as primary key and indices ... ? See both examples. Correction. The case with strings as primary key and indices needs only more ram memory ... keys are indeed much more efficient than String UID primary keys. The main reasons for this (ordered
JPA Doc
23

JPA Annotations for Classes

are useful in representing composite primary keys as explained in the Primary Key section of the ObjectDB manual.
JPA Doc
23

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