ManyToOne and Composite Keys

[jimk1723]

How do you annotate a ManyToOne relationship where the "Many" entitiy has a foreign key field that is also the member of a composite key?

I am starting from Seam `generate-entities`, but the generated code fails when I create new instances of each entity in the same transaction - I'm getting foreign key violations on commit. It's clear the EmbeddedId class is not getting the id value.

[jimk1723]

Here's the code:

package com.mydomain.myproject;

// Generated Apr 13, 2007 6:45:10 PM by Hibernate Tools 3.2.0.b9

import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import org.hibernate.validator.NotNull;

/**
 * Department generated by hbm2java
 */
@Entity
@Table(name = "DEPARTMENT")
public class Department implements java.io.Serializable {

 private long departmentId;

 private Set<DepartmentStrings> departmentStringses = new HashSet<DepartmentStrings>(
 0);

 public Department() {
 }

 public Department(long departmentId) {
 this.departmentId = departmentId;
 }

 public Department(long departmentId,
 Set<DepartmentStrings> departmentStringses) {
 this.departmentId = departmentId;

 this.departmentStringses = departmentStringses;
 }

 @Id
 @Column(name = "DEPARTMENT_ID", unique = true, nullable = false, precision = 16, scale = 0)
 @NotNull
 @GeneratedValue
 public long getDepartmentId() {
 return this.departmentId;
 }

 public void setDepartmentId(long departmentId) {
 this.departmentId = departmentId;
 }

 @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "department")
 public Set<DepartmentStrings> getDepartmentStringses() {
 return this.departmentStringses;
 }

 public void setDepartmentStringses(
 Set<DepartmentStrings> departmentStringses) {
 this.departmentStringses = departmentStringses;
 }

}

package com.mydomain.myproject;
// Generated Apr 13, 2007 6:45:10 PM by Hibernate Tools 3.2.0.b9

import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import org.hibernate.validator.Length;
import org.hibernate.validator.NotNull;

/**
 * DepartmentStrings generated by hbm2java
 */
@Entity
@Table(name = "DEPARTMENT_STRINGS")
public class DepartmentStrings implements java.io.Serializable {

 private DepartmentStringsId id;
 private Department department;
 private String name;

 public DepartmentStrings() {
 }

 public DepartmentStrings(DepartmentStringsId id, Department department) {
 this.id = id;
 this.department = department;
 }
 public DepartmentStrings(DepartmentStringsId id, Department department,
 String name) {
 this.id = id;
 this.department = department;
 this.name = name;
 }

 @EmbeddedId
 @AttributeOverrides({
 @AttributeOverride(name = "departmentId", column = @Column(name = "DEPARTMENT_ID", nullable = false, precision = 16, scale = 0)),
 @AttributeOverride(name = "langCode", column = @Column(name = "LANG_CODE", nullable = false, length = 5))})
 @NotNull
 public DepartmentStringsId getId() {
 return this.id;
 }

 public void setId(DepartmentStringsId id) {
 this.id = id;
 }
 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "DEPARTMENT_ID", nullable = false, insertable = false, updatable = false)
 @NotNull
 public Department getDepartment() {
 return this.department;
 }

 public void setDepartment(Department department) {
 this.department = department;
 }

 @Column(name = "NAME", length = 4000)
 @Length(max = 4000)
 public String getName() {
 return this.name;
 }

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

}

package com.mydomain.myproject;
// Generated Apr 13, 2007 6:45:10 PM by Hibernate Tools 3.2.0.b9

import javax.persistence.Column;
import javax.persistence.Embeddable;
import org.hibernate.validator.Length;
import org.hibernate.validator.NotNull;

/**
 * DepartmentStringsId generated by hbm2java
 */
@Embeddable
public class DepartmentStringsId implements java.io.Serializable {

 private long departmentId;
 private String langCode;

 public DepartmentStringsId() {
 }

 public DepartmentStringsId(long departmentId, String langCode) {
 this.departmentId = departmentId;
 this.langCode = langCode;
 }

 @Column(name = "DEPARTMENT_ID", nullable = false, precision = 16, scale = 0)
 @NotNull
 public long getDepartmentId() {
 return this.departmentId;
 }

 public void setDepartmentId(long departmentId) {
 this.departmentId = departmentId;
 }

 @Column(name = "LANG_CODE", nullable = false, length = 5)
 @NotNull
 @Length(max = 5)
 public String getLangCode() {
 return this.langCode;
 }

 public void setLangCode(String langCode) {
 this.langCode = langCode;
 }

 public boolean equals(Object other) {
 if ((this == other))
 return true;
 if ((other == null))
 return false;
 if (!(other instanceof DepartmentStringsId))
 return false;
 DepartmentStringsId castOther = (DepartmentStringsId) other;

 return (this.getDepartmentId() == castOther.getDepartmentId())
 && ((this.getLangCode() == castOther.getLangCode()) || (this
 .getLangCode() != null
 && castOther.getLangCode() != null && this
 .getLangCode().equals(castOther.getLangCode())));
 }

 public int hashCode() {
 int result = 17;

 result = 37 * result + (int) this.getDepartmentId();
 result = 37 * result
 + (getLangCode() == null ? 0 : this.getLangCode().hashCode());
 return result;
 }

}

[fhh]

Sorry, but your ERM does not make any sense. What are you trying to achieve?

Regards

Felix

[jimk1723]

Sorry, but your ERM does not make any sense. What are you trying to achieve?

The example is a bit contrived; I was simply modeling a Department table that has an association to a DeparmentStrings table which stores a localized name of the department, i.e. the composite key of DeparmentStrings would be (department_id, lang_code) where lang_code is something like "en-us".

I'm really looking for any example where the owning field of a ManyToOne relationship is also part of a composite key (via either IdClass or EmbeddedId.)

[jimk1723]

I think I answered my own question - I was hung up on the seam-gen'ed code; I implemented my own entities which seem to work fine.

I removed the mappedBy attribute on the @OneToMany annotation and added a @JoinColumn annotation - that seemed to fix things.

package com.mydomain.example;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import org.hibernate.validator.NotNull;

/**
 * Department generated by hbm2java
 */
@Entity
@Table(name = "DEPARTMENT")
public class Department implements java.io.Serializable {

 private long departmentId;

 private Set<DepartmentStrings> strings = new HashSet<DepartmentStrings>(0);

 public Department() {
 }

 public Department(long departmentId) {
 this.departmentId = departmentId;
 }

 public Department(long departmentId,
 Set<DepartmentStrings> departmentStringses) {
 this.departmentId = departmentId;

 this.strings = departmentStringses;
 }

 @Id
 @Column(name = "DEPARTMENT_ID", unique = true, nullable = false, precision = 16, scale = 0)
 @NotNull
 @GeneratedValue
 public long getDepartmentId() {
 return this.departmentId;
 }

 public void setDepartmentId(long departmentId) {
 this.departmentId = departmentId;
 }

 @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
 @JoinColumn(name = "DEPARTMENT_ID")
 public Set<DepartmentStrings> getStrings() {
 return this.strings;
 }

 public void setStrings(Set<DepartmentStrings> strings) {
 this.strings = strings;
 }

}

package com.mydomain.example;

import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.Table;

import org.hibernate.validator.NotNull;

/**
 * DepartmentStrings generated by hbm2java
 */
@Entity
@Table(name = "DEPARTMENT_STRINGS")
public class DepartmentStrings implements java.io.Serializable {

 private DepartmentStringsId id;

 private String name;

 public DepartmentStrings() {
 }

 public DepartmentStrings(DepartmentStringsId id) {
 this.id = id;
 }

 @Column(name = "NAME")
 public String getName() {
 return name;
 }

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

 @EmbeddedId
 @AttributeOverrides( {
 @AttributeOverride(name = "department", column = @Column(name = "DEPARTMENT_ID", precision = 16, scale = 0)),
 @AttributeOverride(name = "langCode", column = @Column(name = "LANG_CODE", nullable = false, length = 5)) })
 @NotNull
 public DepartmentStringsId getId() {
 return this.id;
 }

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

package com.mydomain.example;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;

public class DepartmentStringsId implements Serializable {

 private Department department;

 private String langCode;

 public DepartmentStringsId() {
 }

 public DepartmentStringsId(Department department, String langCode) {
 super();
 this.department = department;
 this.langCode = langCode;
 }

 @ManyToOne
 @JoinColumn(name = "DEPARTMENT_ID")
 public Department getDepartment() {
 return department;
 }

 public void setDepartment(Department department) {
 this.department = department;
 }

 @Column(name = "LANG_CODE")
 public String getLangCode() {
 return langCode;
 }

 public void setLangCode(String langCode) {
 this.langCode = langCode;
 }
}

...and some quick TestNG methods:

 @Test(enabled = true)
 public void testCreateWithString() throws Exception {
 EntityManagerFactory emf = Persistence
 .createEntityManagerFactory("ejbexample");
 EntityManager em = emf.createEntityManager();
 em.getTransaction().begin();

 Department d = new Department();

 DepartmentStrings ds1 = new DepartmentStrings(new DepartmentStringsId(
 d, "en-us"));
 ds1.setName("Test name");

 DepartmentStrings ds2 = new DepartmentStrings(new DepartmentStringsId(
 d, "es-mx"));
 ds2.setName("Pruebe el nombre");

 d.getStrings().add(ds1);
 d.getStrings().add(ds2);

 em.persist(d);
 em.getTransaction().commit();

 this.departmentId = d.getDepartmentId();
 }

 @Test(enabled = true, dependsOnMethods = "testCreateWithString")
 public void testLookup() throws Exception {
 EntityManagerFactory emf = Persistence
 .createEntityManagerFactory("ejbexample");
 EntityManager em = emf.createEntityManager();
 Department d = em.find(Department.class, this.departmentId);

 assert d.getStrings().size() == 2;

 for (DepartmentStrings ds : d.getStrings()) {
 assert ds.getName().equals("Test name")
 || ds.getName().equals("Pruebe el nombre");
 }
 }