BAEL-4887: fetching multiple entities in JPA query (#10803)

2021-05-25 21:48:22 +02:00
parent c24379b927
commit 27c53fd6de
6 changed files with 240 additions and 0 deletions
@@ -0,0 +1,43 @@
+package com.baeldung.jpa.returnmultipleentities;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import java.util.Objects;
+
+@Entity
+public class Channel {
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long id;
+
+    private String code;
+
+    private Long subscriptionId;
+
+    public void setCode(String code) {
+        this.code = code;
+    }
+
+    public String getCode() {
+        return code;
+    }
+
+    public void setSubscriptionId(Long subscriptionId) {
+        this.subscriptionId = subscriptionId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Channel channel = (Channel) o;
+        return Objects.equals(id, channel.id) && Objects.equals(code, channel.code) && Objects.equals(subscriptionId, channel.subscriptionId);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, code, subscriptionId);
+    }
+}
@@ -0,0 +1,23 @@
+package com.baeldung.jpa.returnmultipleentities;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+import javax.persistence.Query;
+import java.util.List;
+
+public class ReportRepository {
+    private final EntityManagerFactory emf;
+
+    public ReportRepository() {
+        emf = Persistence.createEntityManagerFactory("jpa-h2-return-multiple-entities");
+    }
+
+    public List<Object[]> find(String email) {
+        EntityManager entityManager = emf.createEntityManager();
+        Query query = entityManager.createQuery("SELECT c, s, u FROM  Channel c, Subscription s, User u WHERE c.subscriptionId = s.id AND s.id = u.subscriptionId AND u.email=:email");
+        query.setParameter("email", email);
+
+        return query.getResultList();
+    }
+}
@@ -0,0 +1,41 @@
+package com.baeldung.jpa.returnmultipleentities;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import java.util.Objects;
+
+@Entity
+public class Subscription {
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long id;
+
+    private String code;
+
+    public void setCode(String code) {
+        this.code = code;
+    }
+
+    public String getCode() {
+        return code;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Subscription subscription = (Subscription) o;
+        return Objects.equals(id, subscription.id) && Objects.equals(code, subscription.code);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, code);
+    }
+}
@@ -0,0 +1,29 @@
+package com.baeldung.jpa.returnmultipleentities;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class User {
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long id;
+
+    private String email;
+
+    private Long subscriptionId;
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public void setSubscriptionId(Long subscriptionId) {
+        this.subscriptionId = subscriptionId;
+    }
+}