CODEWITHSUNDEEP
javajpa
Aditya
Aditya

Reputation: 53

Composite Primary and foreign key jpa

I have two tables T1 and T2. T1 has id(PK), name , type. T2 has SID, TID, Type. Primary Key for T2 is combination of all 3: SID, TID, Type. Now SID and TID are foreign keys also mapped to ID of T1. Someone please help how to make this in JPA.

package com.sap.table;

import java.io.Serializable;
import java.lang.String;
import javax.persistence.*;

import static javax.persistence.GenerationType.TABLE;
import static javax.persistence.GenerationType.IDENTITY;

/**
 * Entity implementation class for Entity: Relations
 *
 */
@IdClass(RelationsPK.class)
@Entity
@Table (name = "demo_relations11")


public class Relations implements Serializable {


    //@EmbeddedId
    //@JoinColumn(referencedColumnName="AssetID")
//private RelationsPK Relations_PK;
//  @Id
////    @JoinColumn(referencedColumnName="AssetID")
//  private String TargetID;
@Id
private String Type;
private static final long serialVersionUID = 1L;

//    @MapsId("SourceID")
@Id
@ManyToOne(targetEntity=Asset.class)

@JoinColumns({
    @JoinColumn(name="SourceID", referencedColumnName="AssetID"),
    @JoinColumn(name="TargetID", referencedColumnName="AssetID")
})
//@JoinColumn(referencedColumnName="AssetID") 

Asset asset;



public Asset getAsset() {
    return asset;
}
public void setAsset(Asset asset) {
    this.asset = asset;
}
public Relations() {
    super();  
}   
//  public String getSourceID() {
//      return this.SourceID;
//  }
//
//  public void setSourceID(String SourceID) {
//      this.SourceID = SourceID;
//  }   
//  public String getTargetID() {
//      return this.TargetID;
//  }
//
//  public void setTargetID(String TargetID) {
//      this.TargetID = TargetID;
//  }   
public String getType() {
    return this.Type;
}

public void setType(String Type) {
    this.Type = Type;
}

}

T1 - ID(PK), Name, Type T2 - SID (FK to ID), TID (FK to ID), Type PK of T2 - SID,TID,Type

Upvotes: 3

Views: 2417

Answers (1)

Aditya
Aditya

Reputation: 53

I have found the solution. First of all i used @IdClass Notation. That is made another class for the primary key. Then used @Id for annotating in my class to annotated. I also used

  @JoinColumn(name = "")
  @ManyToOne(targetEntity = parent_class)

I used the above annotation for all the primary keys referencing the parent table.

Upvotes: 1

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