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JPA Enum Constant in javax.persistence.GenerationType IDENTITY Indicates that the persistence provider must assign primary keys for the entity using a database identity column. Since: JPA 1.0

, as explained in the previous section . The Identity Strategy The IDENTITY strategy is very similar ... = GenerationType . IDENTITY ) long id; : } The IDENTITY strategy also generates an automatic value during commit for every new entity object. The difference is that a separate identity generator is managed

. In addition, only instances of entity classes preserve identity and are stored ... can save space in the database and improve efficiency. Embeddable classes, however, do not have an identity

, comparing the content rather than the identity . Date values can be compared by using any comparison operator ... , comparing the content rather than the identity . Values of the boolean and Boolean types can be compared by

of the query result cache. Caching results is very useful for recurring queries with identical arguments

) FROM Country AS c This query is identical to the previous query above except that now the result

/ Write operations. The other (slave) nodes in the cluster manage identical copies of the same database

with the same identity (i.e. same type and primary key). If the EntityManager does not manage such an entity

the different notation, named parameters and ordinal parameters are identical . Named parameters can provide

this regard, orphanRemoval=true and cascade=CascadeType.REMOVE are identical , and if orphanRemoval

and do not have their own separate identity . Automatic Primary Key By default, the primary key

.removeChild(ContainerBase.java:1049) [...] Caused by: javax.jdo.JDONullIdentityException: The identity must not be null.         at javax.jdo. identity .SingleFieldIdentity ... . identity .ObjectIdentity. (ObjectIdentity.java:60)         at com

JDO Class LongIdentity java.lang.Object ∟  javax.jdo. identity .SingleFieldIdentity ∟  javax.jdo. identity .LongIdentity This class is for identity with a single long field. Since: JDO 1.0 ... of identity objects. Parameters: o - Other identity Return: The relative ordering between the objects

JDO Class IntIdentity java.lang.Object ∟  javax.jdo. identity .SingleFieldIdentity ∟  javax.jdo. identity .IntIdentity This class is for identity with a single int field. Since: JDO 1.0 Public ... of identity objects. Parameters: o - Other identity Return: The relative ordering between the objects

JDO Class ObjectIdentity java.lang.Object ∟  javax.jdo. identity .SingleFieldIdentity ∟  javax.jdo. identity .ObjectIdentity This class is for identity with a single Object type field ... ) Determine the ordering of identity objects. Parameters: o - Other identity Return: The relative

JDO Class ByteIdentity java.lang.Object ∟  javax.jdo. identity .SingleFieldIdentity ∟  javax.jdo. identity .ByteIdentity This class is for identity with a single byte field. Since: JDO 1.0 ... ) Determine the ordering of identity objects. Parameters: o - Other identity Return: The relative ordering

JDO Class CharIdentity java.lang.Object ∟  javax.jdo. identity .SingleFieldIdentity ∟  javax.jdo. identity .CharIdentity This class is for identity with a single character field. Since: JDO 1 ... .0 Public Methods int compareTo (Object o) Determine the ordering of identity objects

JDO Class ShortIdentity java.lang.Object ∟  javax.jdo. identity .SingleFieldIdentity ∟  javax.jdo. identity .ShortIdentity This class is for identity with a single short field. Since: JDO 1.0 ... the ordering of identity objects. Parameters: o - Other identity Return: The relative ordering between

JDO Class StringIdentity java.lang.Object ∟  javax.jdo. identity .SingleFieldIdentity ∟  javax.jdo. identity .StringIdentity This class is for identity with a single String field. Since: JDO 1 ... the ordering of identity objects. Parameters: o - Other identity Return: The relative ordering

JDO Class SingleFieldIdentity java.lang.Object ∟  javax.jdo. identity .SingleFieldIdentity ... for all single field identity classes. A common case of application identity uses exactly one persistent field in the class to represent identity . In this case, the application can use a standard JDO

JDO Enum Constant in javax.jdo.annotations.IdGeneratorStrategy IDENTITY Since: JDO 2.1

-superclass attribute. identity -type and objectid-class The identity -type and objectid-class attributes ... database, ObjectDB always uses datastore identity with its own object-id class). 4.3   ... in the JDO specification, is irrelevant when using datastore identity , which is the only object

assigned automatically by the JDO implementation as datastore identity . Application identity , in

JDO supports two modes of persistable classes that can be set by the following annotations: Non persistable classes that should be enhanced (because of accessing persistent fields of other classes directly) can be marked with: The identity mode of persistence capable classes can be specified by using:

: Equality operators ( == , != ) compare the identity of instances of user persistent classes (as in Java

representation of the object id, or an object representation of a single field identity key Return ... method attempts to find an instance in the cache with the specified JDO identity . The oid parameter ... is false , and there is already an instance in the cache with the same JDO identity as the oid parameter

, object identity , and version if it has one. In the Reference Implementation, the JDO Enhancer modifies ... this PersistenceCapable instance to the Object Id instance. For classes using single field identity ... . For classes using single field identity , this method always throws JDOUserException . Parameters

) The ObjectId returned by this method represents the JDO identity of the instance. The ObjectId is a copy (clone) of the internal state of the instance, and changing it does not affect the JDO identity of the instance. The getObjectId method returns an ObjectId instance that represents the object identity

of this PersistenceCapable class. It is intended only for application identity . This method should not be called for classes that use single field identity ; newObjectIdInstance(Class, Object) should be used instead. If the class has been enhanced for datastore identity , or if the class is abstract, null

) Return a copy of the JDO identity associated with the parameter instance. Persistent instances of PersistenceCapable classes have a JDO identity managed by the PersistenceManager . This method returns a copy of the ObjectId that represents the JDO identity . Transient instances and instances

the cache with the specified JDO identity . The oid parameter object might have been returned by ... in the cache with the same JDO identity as the oid parameter, then this method returns ... the cache with the same JDO identity as the oid parameter, then this method creates an instance

(PersistenceCapable pc) Return the object representing the JDO identity of the calling instance. If the JDO identity is being changed in the current transaction, this method returns the identity ... Return: the object representing the JDO identity of the calling instance Since: JDO 1.0

 o ) Create a new instance of the class used for JDO identity , using the key constructor of the object id class. It is intended for single field identity . The identity instance returned ... . For classes that use single field identity , if the parameter is of one of the following types, the behavior

Class for JDO identity , using the key constructor of the object id class. It is intended for single field identity . The identity instance returned has no relationship with the values of the primary key ... class for the object id class, null is returned. For classes that use single field identity

getObjectId (Object pc) Return a copy of the JDO identity associated with the parameter instance. Persistent instances of PersistenceCapable classes have a JDO identity managed by the PersistenceManager . This method returns a copy of the ObjectId that represents the JDO identity . Instances unknown by

identity associated with this instance. Persistent instances of PersistenceCapable classes have a JDO identity managed by the PersistenceManager. This method returns a copy of the ObjectId that represents the JDO identity . Transient instances return null. The ObjectId may be serialized and later

a copy of the JDO identity associated with the parameter instance. Persistent instances of PersistenceCapable classes have a JDO identity managed by the PersistenceManager . This method returns a copy of the ObjectId that represents the JDO identity . Transient instances and instances of classes

Annotation for the datastore identity of the class. Corresponds to the xml element "datastore- identity ... of the column for the datastore identity Since: JDO 2.1 Column [] columns default {} The column(s) making up the datastore identity . Since: JDO 2.1 String customStrategy default "" Custom strategy to use

) Return a copy of the JDO identity associated with the parameter instance. Persistent instances of PersistenceCapable classes have a JDO identity managed by the PersistenceManager . This method returns a copy of the ObjectId that represents the JDO identity . Instances unknown by the implementation

) Return the Class that implements the JDO Identity for the specified PersistenceCapable class. The application can use the returned Class to construct a JDO Identity instance for application identity PersistenceCapable classes. This JDO Identity instance can then be used to get an instance

;PersistenceCapable pc ) Return the object representing the JDO identity of the calling instance. If the JDO identity is being changed in the current transaction, this method returns the current identity as ... : the object representing the JDO identity of the calling instance Since: JDO 1.0

;pc ) Return the object representing the JDO identity of the calling instance. If the JDO identity is being changed in the current transaction, this method returns the identity as of the beginning ... representing the JDO identity of the calling instance Since: JDO 1.0

 pc ) The ObjectId returned by this method represents the JDO identity of the instance ... identity of the instance. If the object identity is being changed in the transaction, by ... identity in the transaction. If there is no transaction in progress, or if none of the key fields

identity . It is intended only for application identity . If the class has been enhanced for datastore identity , or if the class is abstract, null is returned. For classes using single field identity

only for application identity . This method should not be called for classes that use single field identity ; newObjectIdInstance(Class, Object) should be used instead. If the class has been enhanced for datastore identity , or if the class is abstract, null is returned. Parameters: pcClass

JDO Method in javax.jdo. identity .IntIdentity int compareTo (   Object o ) Determine the ordering of identity objects. Parameters: o - Other identity Return: The relative ordering between the objects Since: JDO 2.2

JDO Method in javax.jdo. identity .ObjectIdentity int compareTo (   Object o ) Determine the ordering of identity objects. Parameters: o - Other identity Return: The relative ordering between the objects Since: JDO 2.2

JDO Method in javax.jdo. identity .LongIdentity int compareTo (   Object o ) Determine the ordering of identity objects. Parameters: o - Other identity Return: The relative ordering between the objects Since: JDO 2.2

JDO Method in javax.jdo. identity .CharIdentity int compareTo (   Object o ) Determine the ordering of identity objects. Parameters: o - Other identity Return: The relative ordering between the objects Since: JDO 2.2

JDO Method in javax.jdo. identity .ByteIdentity int compareTo (   Object o ) Determine the ordering of identity objects. Parameters: o - Other identity Return: The relative ordering between the objects Since: JDO 2.2