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JPA Annotation IdClass Target: TYPE Implemented Interfaces: Annotation Specifies a composite primary key type whose fields or properties map to the plain fields or properties of the annotated entity ... . The primary key type does not itself need to be annotated. Example: {@snippet : @ IdClass (EmployeePK

JPA Annotation Attribute in jakarta.persistence. IdClass Class value default null The primary key class, which must declare fields or properties with names and types that match the Id fields and properties of the annotated entity class. Since: JPA 1.0

, the primary key of the following Project entity class consists of two fields: @Entity @ IdClass ... class using the @ IdClass annotation. The ID class reflects the primary key fields and its objects

a persistence unit, An entity or IdClass class should implement the java.io.Serializable interface).

a Map, and uses a Compound Primary Key. The contained class therefore uses an @ IdClass . This all works ... .persistence.Id; import javax.persistence. IdClass ; import javax.persistence.ManyToOne; import javax.persistence.Version; @Entity @ IdClass (CompoundKeyMapItem.CompoundKeyMapItemId.class) public class

, and the entity class must not declare an IdClass . The embedded primary key type must implement equals ... key type are not supported. Example 1: {@snippet : See Also: Embeddable MapsId IdClass Since: JPA 1.0

I know the following 2 ways to declare a composite Primary key: ********* Solution 1 ********* @Entity @ IdClass (CompositePK.class) public class A {     @Id private long uid ... only for entity objects (and not for embeddable classes). Consider using: @ IdClass (ZoneId.class

for an idclass . Return: boolean indicating whether the identifiable type has a single id attribute Inherited

. If the primary key is a composite primary key and is mapped as IdClass , an instance of the primary key class is used as the key. Since: JPA 1.0

the map key. If the primary key is a composite primary key and is mapped as IdClass , an instance of the primary key class is used as the key. Since: JPA 1.0

id attribute. Returns true for a simple id or embedded id; returns false for an idclass . Return

for a simple id or embedded id; returns false for an idclass . Return: boolean indicating

JPA Method in jakarta.persistence.metamodel.IdentifiableType boolean hasSingleIdAttribute () Whether the identifiable type has a single id attribute. Returns true for a simple id or embedded id; returns false for an idclass . Return: boolean indicating whether the identifiable type has a single id attribute Since: JPA 2.0

@ IdClass (PersonId.class) public class Person { public enum Gender {FEMALE, MALE}; @Id private String id

." This is a NetBeans restriction, not a JPA restriction. "An entity or IdClass class should implement the java.io

;  private Map assignements; } @Entity @ IdClass (Assignement.PK.class) public class Assignement

") @ IdClass (Video.VideoId.class) public class Video { protected String provider; protected String