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Jakarta Persistence (JPA) Annotation Type jakarta.persistence. IdClass Implemented Interfaces: Annotation Target: Type Specifies a composite primary key type whose fields or properties map ... to be annotated. Example: @ IdClass (EmployeePK.class) @Entity public class Employee { @Id String empName; @Id

Jakarta Persistence (JPA) Method in jakarta.persistence. IdClass Class value 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: Jakarta Persistence (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).

of the entity may be annotated Id or EmbeddedId , and the entity class must not declare an IdClass ... ; } See Also: Embeddable MapsId IdClass Since: Jakarta Persistence (JPA) 1.0 The JPA Primary Key article explains

and is mapped as IdClass , an instance of the primary key class is used as the key. Default

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

false for an idclass . Inherited from IdentifiableType Returns: boolean indicating

for an idclass . Inherited from IdentifiableType Returns: boolean indicating whether the identifiable

Jakarta Persistence (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 . Returns: boolean indicating whether the identifiable

. If the primary key is a composite primary key and is mapped as IdClass , an instance of the primary

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

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

@ 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 ; import java.io.Serial; import java.io.Serializable; import java.util.Objects; @Entity @ IdClass

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