Bael 1908 - Guide to SqlResultSetMapping (#4586)

* Commit for Eval Article pull request

* Revert "Commit for Eval Article pull request"

* BAEL-1908 Initial Commit

persistence-modules/java-jpa/pom.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../pom.xml</relativePath>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>java-jpa</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.hibernate</groupId>
+            <artifactId>hibernate-core</artifactId>
+            <version>${hibernate.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <version>${h2.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <hibernate.version>5.3.1.Final</hibernate.version>
+        <h2.version>1.4.197</h2.version>
+    </properties>
+</project>

persistence-modules/java-jpa/src/main/java/com/baeldung/sqlresultsetmapping/Employee.java

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+package com.baeldung.sqlresultsetmapping;
+
+import javax.persistence.*;
+
+
+@SqlResultSetMapping(
+        name="EmployeeResult",
+        entities={
+                @EntityResult(
+                        entityClass = com.baeldung.sqlresultsetmapping.Employee.class,
+                        fields={@FieldResult(name="id",column="employeeNumber"),
+                                 @FieldResult(name="name", column="name")}
+                )
+        }
+)
+@NamedNativeQuery(
+        name="Employees",
+        query="SELECT id as employeeNumber, name FROM EMPLOYEE",
+        resultSetMapping = "EmployeeResult"
+)
+@Entity
+public class Employee {
+
+    @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;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/sqlresultsetmapping/ScheduledDay.java

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+package com.baeldung.sqlresultsetmapping;
+
+import javax.persistence.*;
+
+@SqlResultSetMappings(value = {
+    @SqlResultSetMapping(name = "ScheduleResult",
+        classes = { @ConstructorResult(targetClass = com.baeldung.sqlresultsetmapping.ScheduledDay.class,
+        columns = { @ColumnResult(name = "id", type = Long.class),
+                    @ColumnResult(name = "employeeId", type = Long.class),
+                    @ColumnResult(name = "hourIn"),
+                    @ColumnResult(name = "hourOut"),
+                    @ColumnResult(name = "dayOfWeek") }) }),
+    @SqlResultSetMapping(name = "FridayEmployeeResult",
+                         columns = { @ColumnResult(name = "employeeId") }),
+    @SqlResultSetMapping(name = "EmployeeScheduleResults",
+                         entities = { @EntityResult(entityClass = com.baeldung.sqlresultsetmapping.Employee.class),
+                                      @EntityResult(entityClass = com.baeldung.sqlresultsetmapping.ScheduledDay.class)
+    }) })
+@NamedNativeQuery(name = "FridayEmployees",
+        query = "SELECT employeeId FROM schedule_days WHERE dayOfWeek = 'FRIDAY'",
+        resultSetMapping = "FridayEmployeeResult")
+
+@NamedNativeQuery(name = "Schedules",
+        query = "SELECT * FROM schedule_days WHERE hourIn = 8",
+        resultSetMapping = "ScheduleResult")
+@Entity
+@Table(name = "SCHEDULE_DAYS")
+public class ScheduledDay {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+    private Long employeeId;
+    private Integer hourIn;
+    private Integer hourOut;
+    private String dayOfWeek;
+
+    public ScheduledDay() {
+    }
+
+    public ScheduledDay(Long id, Long employeeId, Integer hourIn, Integer hourOut, String dayofWeek) {
+        this.id = id;
+        this.employeeId = employeeId;
+        this.hourIn = hourIn;
+        this.hourOut = hourOut;
+        this.dayOfWeek = dayofWeek;
+    }
+
+    public Long getEmployeeId() {
+        return employeeId;
+    }
+
+    public void setEmployeeId(Long employeeId) {
+        this.employeeId = employeeId;
+    }
+
+    public Integer getHourIn() {
+        return hourIn;
+    }
+
+    public void setHourIn(Integer hourIn) {
+        this.hourIn = hourIn;
+    }
+
+    public Integer getHourOut() {
+        return hourOut;
+    }
+
+    public void setHourOut(Integer hourOut) {
+        this.hourOut = hourOut;
+    }
+
+    public String getDayOfWeek() {
+        return dayOfWeek;
+    }
+
+    public void setDayOfWeek(String dayOfWeek) {
+        this.dayOfWeek = dayOfWeek;
+    }
+}

persistence-modules/java-jpa/src/main/resources/META-INF/persistence.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
+             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
+             http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
+             version="2.1">
+
+    <persistence-unit name="java-jpa-scheduled-day">
+        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+        <class>com.baeldung.sqlresultsetmapping.ScheduledDay</class>
+        <properties>
+            <property name="javax.persistence.jdbc.driver" value="org.h2.Driver" />
+            <property name="javax.persistence.jdbc.url"
+                      value="jdbc:h2:mem:test;INIT=RUNSCRIPT FROM 'classpath:database.sql'" />
+            <property name="javax.persistence.jdbc.user" value="sa" />
+            <property name="javax.persistence.jdbc.password" value="" />
+            <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
+            <!--<property name="hibernate.hbm2ddl.auto" value="create-drop" />-->
+            <property name="show_sql" value="true"/>
+            <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>
+        </properties>
+    </persistence-unit>
+</persistence>

persistence-modules/java-jpa/src/main/resources/database.sql

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+CREATE TABLE EMPLOYEE
+(id BIGINT,
+ name VARCHAR(10));
+
+INSERT INTO EMPLOYEE VALUES (1, 'JOHN');
+INSERT INTO EMPLOYEE VALUES (2, 'MARY');
+INSERT INTO EMPLOYEE VALUES (3, 'FRANK');
+
+CREATE TABLE SCHEDULE_DAYS
+(id IDENTITY,
+ employeeId BIGINT,
+ hourIn     int,
+ hourOut    int,
+ dayOfWeek  VARCHAR(10));
+
+INSERT INTO SCHEDULE_DAYS (employeeId, hourIn, hourOut, dayOfWeek) VALUES (1, 13, 21, 'FRIDAY');
+INSERT INTO SCHEDULE_DAYS (employeeId, hourIn, hourOut, dayOfWeek) VALUES (2, 8, 4, 'SATURDAY');
+INSERT INTO SCHEDULE_DAYS (employeeId, hourIn, hourOut, dayOfWeek) VALUES (3, 8, 4, 'MONDAY');
+INSERT INTO SCHEDULE_DAYS (employeeId, hourIn, hourOut, dayOfWeek) VALUES (3, 8, 4, 'FRIDAY');

persistence-modules/java-jpa/src/test/java/com/baeldung/sqlresultsetmapping/SqlResultSetMappingUnitTest.java

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+package com.baeldung.sqlresultsetmapping;
+
+import static org.junit.Assert.*;
+
+import org.junit.jupiter.api.*;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+import javax.persistence.Query;
+import java.util.Collections;
+import java.util.List;
+
+public class SqlResultSetMappingUnitTest {
+
+    private static EntityManager em;
+    private static EntityManagerFactory emFactory;
+
+    @BeforeAll
+    public static void setup() {
+        emFactory = Persistence.createEntityManagerFactory("java-jpa-scheduled-day");
+        em = emFactory.createEntityManager();
+    }
+
+    @Test
+    public void whenNamedQuery_thenColumnResult() {
+        List<Long> employeeIds = em.createNamedQuery("FridayEmployees").getResultList();
+        assertEquals(2, employeeIds.size());
+    }
+
+    @Test
+    public void whenNamedQuery_thenConstructorResult() {
+        List<ScheduledDay> scheduleDays = Collections.checkedList(em.createNamedQuery("Schedules", ScheduledDay.class).getResultList(), ScheduledDay.class);
+        assertEquals(3, scheduleDays.size());
+        assertTrue(scheduleDays.stream().allMatch(c -> c.getHourIn().longValue() == 8));
+    }
+
+    @Test
+    public void whenNamedQuery_thenSingleEntityResult() {
+        List<Employee> employees = Collections.checkedList(em.createNamedQuery("Employees").getResultList(), Employee.class);
+        assertEquals(3, employees.size());
+        assertTrue(employees.stream().allMatch(c -> c.getClass() == Employee.class));
+    }
+
+    @Test
+    public void whenNamedQuery_thenMultipleEntityResult() {
+        final Query query = em.createNativeQuery("SELECT e.id, e.name, d.id, d.employeeId, "
+                                                    + " d.dayOfWeek, d.hourIn, d.hourOut "
+                                                    + " FROM employee e, schedule_days d "
+                                                    + " WHERE e.id = d.employeeId", "EmployeeScheduleResults");
+        List<Object[]> results = query.getResultList();
+        assertEquals(4, results.size());
+        assertTrue(results.get(0).length == 2);
+
+        Employee emp = (Employee) results.get(1)[0];
+        ScheduledDay day = (ScheduledDay) results.get(1)[1];
+
+        assertTrue(day.getEmployeeId() == emp.getId());
+    }
+
+    @AfterAll
+    public static void destroy() {
+
+        if (em != null) {
+            em.close();
+        }
+        if (emFactory != null) {
+            emFactory.close();
+        }
+    }
+}

persistence-modules/java-jpa/src/test/resources/employees.sql

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+INSERT INTO employee (1, "JOHN");
+INSERT INTO employee (2, "MARY");
+INSERT INTO employee (3, "FRANK");

persistence-modules/java-jpa/src/test/resources/scheduledDays.sql

@@ -0,0 +1,10 @@
+INSERT INTO SCHEDULE_DAYS (1, 13, 21, 'FRIDAY');
+INSERT INTO SCHEDULE_DAYS (2, 8, 4, 'SATURDAY');
+INSERT INTO SCHEDULE_DAYS (3, 8, 4, 'FRIDAY');
+
+
+--    private Long id;
+--    private Long employeeId;
+--    private Time in;
+--    private Time out;
+--    private DayOfWeek dayOfWeek;