From 5f025f6dd179aaeffedf307bcfc2492ac05ac121 Mon Sep 17 00:00:00 2001
From: Seremba Patrick <45463621+Seremba@users.noreply.github.com>
Date: Sat, 8 Jul 2023 06:56:26 +0300
Subject: [PATCH] Difference Between @JoinColumn and @PrimaryKeyJoinColumn in
 JPA (#14171)

* primarykeyjoincolum annotaion in jpa

* indent Departmnet Person and primaryKeyJoinColumn

* indent Department Perspn and PrimaryKeyJoinColumnIntegrationTest classes

* format properly

* format to 2-space continuation identation

* Revert "format to 2-space continuation identation"

This reverts commit 49630409ee296c07cfd494e46f9dbba75c9a49b0.

* add 2-space indent on line continuations.
---
 .../primarykeyjoincolumn/Department.java      | 32 ++++++++++++
 .../primarykeyjoincolumn/Person.java          | 49 +++++++++++++++++
 .../PrimaryKeyJoinColumnIntegrationTest.java  | 52 +++++++++++++++++++
 3 files changed, 133 insertions(+)
 create mode 100644 persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/primarykeyjoincolumn/Department.java
 create mode 100644 persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/primarykeyjoincolumn/Person.java
 create mode 100644 persistence-modules/hibernate-annotations/src/test/java/com/baeldung/hibernate/primarykeyjoincolumn/PrimaryKeyJoinColumnIntegrationTest.java

diff --git a/persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/primarykeyjoincolumn/Department.java b/persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/primarykeyjoincolumn/Department.java
new file mode 100644
index 0000000000..578cc70e38
--- /dev/null
+++ b/persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/primarykeyjoincolumn/Department.java
@@ -0,0 +1,32 @@
+package com.baeldung.hibernate.primarykeyjoincolumn;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+
+@Entity
+@Table(name = "department")
+public class Department {
+
+    @Id
+    private Long id;
+
+    private String name;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+}
diff --git a/persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/primarykeyjoincolumn/Person.java b/persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/primarykeyjoincolumn/Person.java
new file mode 100644
index 0000000000..0dfa11541b
--- /dev/null
+++ b/persistence-modules/hibernate-annotations/src/main/java/com/baeldung/hibernate/primarykeyjoincolumn/Person.java
@@ -0,0 +1,49 @@
+package com.baeldung.hibernate.primarykeyjoincolumn;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToOne;
+import jakarta.persistence.PrimaryKeyJoinColumn;
+import jakarta.persistence.Table;
+
+@Entity
+@Table(name = "person")
+public class Person {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String name;
+
+    @OneToOne
+    @PrimaryKeyJoinColumn
+    private Department department;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Department getDepartment() {
+        return department;
+    }
+
+    public void setDepartment(Department department) {
+        this.department = department;
+    }
+
+}
diff --git a/persistence-modules/hibernate-annotations/src/test/java/com/baeldung/hibernate/primarykeyjoincolumn/PrimaryKeyJoinColumnIntegrationTest.java b/persistence-modules/hibernate-annotations/src/test/java/com/baeldung/hibernate/primarykeyjoincolumn/PrimaryKeyJoinColumnIntegrationTest.java
new file mode 100644
index 0000000000..0a595d4052
--- /dev/null
+++ b/persistence-modules/hibernate-annotations/src/test/java/com/baeldung/hibernate/primarykeyjoincolumn/PrimaryKeyJoinColumnIntegrationTest.java
@@ -0,0 +1,52 @@
+package com.baeldung.hibernate.primarykeyjoincolumn;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
+import jakarta.persistence.Persistence;
+
+public class PrimaryKeyJoinColumnIntegrationTest {
+
+    private static EntityManagerFactory emf;
+
+    private EntityManager em;
+
+    @Before
+    public void setup() {
+        emf = Persistence.createEntityManagerFactory("com.baeldung.movie_catalog");
+        em = emf.createEntityManager();
+        em.getTransaction()
+          .begin();
+        Department department = new Department();
+        department.setName("IT");
+        em.persist(department);
+        Person person = new Person();
+        person.setName("John Doe");
+        person.setDepartment(department);
+        em.persist(person);
+        em.getTransaction()
+          .commit();
+    }
+
+    @After
+    public void teardown() {
+        em.close();
+        emf.close();
+    }
+
+    @Test
+    public void givenPersonEntity_getDepartment_shouldExist() {
+        Person person = em.find(Person.class, 1L);
+        assertNotNull(person);
+        assertEquals("John Doe", person.getName());
+        assertNotNull(person.getDepartment());
+        assertEquals("IT", person.getDepartment()
+         .getName());
+    }
+}