Multiple Column Join

[Michelle Nicholes]

I have class A, class B, and Class C. B is a child of A and C is a child of B. The classes listed below are the ones created by JPA. But I got an error on the reference from C to B as generated. So then I changed the C class to the second list of C below and it compiled. But when I published to Glassfish, I get an error and JPA didnt like it. Could someone please help here?

package com.lmco.birdseye.entity;

import java.io.Serializable;
import javax.persistence.*;
import java.util.Set;

/**
 * The persistent class for the [A] database table.
 * 
 */
@Entity
@Table(name="[A]")
public class A extends com.lmco.util.jpa.Entity implements Serializable {
	private static final long serialVersionUID = 1L;

	@Id
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	private Integer id;

	private String name;

	//bi-directional many-to-one association to B
	@OneToMany(mappedBy="a")
	private Set<B> bs;

    public A() {
    }

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Set<B> getBs() {
		return this.bs;
	}

	public void setBs(Set<B> bs) {
		this.bs = bs;
	}
	
}

package com.lmco.birdseye.entity;

import java.io.Serializable;
import javax.persistence.*;
import java.util.Set;

/**
 * The persistent class for the B database table.
 * 
 */
@Entity
public class B extends com.lmco.util.jpa.Entity implements Serializable {
	private static final long serialVersionUID = 1L;

	@Id
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	private Integer id;

	private String name;

	//bi-directional many-to-one association to A
    @ManyToOne
	@JoinColumn(name="Aid")
	private A a;

	//bi-directional many-to-one association to C
	@OneToMany(mappedBy="b")
	private Set<C> cs;

    public B() {
    }

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public A getA() {
		return this.a;
	}

	public void setA(A a) {
		this.a = a;
	}
	
	public Set<C> getCs() {
		return this.cs;
	}

	public void setCs(Set<C> cs) {
		this.cs = cs;
	}	
}

package com.lmco.birdseye.entity;

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


/**
 * The persistent class for the C database table.
 * 
 */
@Entity
public class C extends com.lmco.util.jpa.Entity implements Serializable {
	private static final long serialVersionUID = 1L;

	@Id
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	private Integer id;

	private String name;

	//bi-directional many-to-one association to B
    @ManyToOne
	@JoinColumns({
		@JoinColumn(name="Aid", referencedColumnName="Aid"),
		@JoinColumn(name="Bid")
		})
	private B b;

    public C() {
    }

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public B getB() {
		return this.b;
	}

	public void setB(B b) {
		this.b = b;
	}	
}

package com.lmco.birdseye.entity;

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


/**
 * The persistent class for the C database table.
 * 
 */
@Entity
public class C extends com.lmco.util.jpa.Entity implements Serializable {
	private static final long serialVersionUID = 1L;

	@Id
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	private Integer id;

	private String name;

	//bi-directional many-to-one association to B
    @ManyToOne
	@JoinColumns({
		@JoinColumn(name="Aid", referencedColumnName="Aid"),
		@JoinColumn(name="Bid", referencedColumnName="id")
		})
	private B b;

    public C() {
    }

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public B getB() {
		return this.b;
	}

	public void setB(B b) {
		this.b = b;
	}
}

[Koen Aerts]

Please use code tags for your code. Also, what is the exact error you're getting?

[Michelle Nicholes]

Well, I found the problem with the above scenario just after I posted the question. add , nullable=false, updatable=false to the JoinColmn reference and it worked.

[Michelle Nicholes]

Wondering how I unmark this resolved. At first I thought I found the answer but evidently not. The app had both my real code and the ABC example. So when it stopped failing on the ABC, I thought it was resolved but once I changed my real code like the ABC, then new issues came up. So, do I create a new question or do we go on with what I did post?

[Vijitha Kumara]

Michelle Streeter wrote:...So, do I create a new question or do we go on with what I did post?

What's the new issues (with exceptions etc...) you face now?

And make sure to use code tags (UseCodeTags) next time posting code. I've edited this time for you...