Named Queries in Hibernate
- 2nd Mar 2017
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Let us understand about Named Queries in Hibernate
If we want to use same queries in multiple places of an application, then instead of writing same query in multiple places, we can define the query in one place with the name assigned to it and use that name in all the places wherever required.
The concept of defining the query with name in one place and accessing that query by using its query name wherever required is called Named Query.
Named query will be defined in the hibernate mapping file.
Named query can be used for both HQL queries and Native SQL queries.
Hibernate Named query example with HQL
< query name=”hql_select_employee“ >from Employee e where e.id=:empId< /query >
For HQL named query, < query > tag should be used.
we have given the name to it, so that we can access the query with that name from required class.
We can also pass the dynamic parameters as well to named query as shown above
Accessing the HQL named query in our class
Query query = session.getNamedQuery(“hql_select_employee”); query.setParameter("empId",new Integer(1));
Hibernate Named query example with SQL
< sql-query name=”sql_select_employee“ >select * from Employee e where e.id=:empId</sql-query>
For SQL named query, < sql-query > tag should be used.
we have given the name to it, so that we can access the query with that name from required class.
We can also pass the dynamic parameters as well to named query as shown above.
Accessing the SQL named query in our class
Query query = session.getNamedQuery(“sql_select_employee”); query.setParameter("empId",new Integer(1));
We can define Named query using either XML mapping or Annotation mapping.
Let us see the complete Project on Named Query
Step 1
Create hibernate project
Please refer Hibernate setup in eclipse article on how to do it.
Project structure
Step 2
Update pom.xml with MYSQL and Hibernate depenedencies
- <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">
- <modelVersion>4.0.0</modelVersion>
- <groupId>NamedQuery</groupId>
- <artifactId>NamedQuery</artifactId>
- <version>0.0.1-SNAPSHOT</version>
- <packaging>jar</packaging>
- <name>NamedQuery</name>
- <url>http://maven.apache.org</url>
- <properties>
- <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
- </properties>
- <dependencies>
- <dependency>
- <groupId>junit</groupId>
- <artifactId>junit</artifactId>
- <version>3.8.1</version>
- <scope>test</scope>
- </dependency>
- <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
- <dependency>
- <groupId>org.hibernate</groupId>
- <artifactId>hibernate-core</artifactId>
- <version>5.2.6.Final</version>
- </dependency>
- <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
- <dependency>
- <groupId>mysql</groupId>
- <artifactId>mysql-connector-java</artifactId>
- <version>6.0.5</version>
- </dependency>
- </dependencies>
- </project>
<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"> <modelVersion>4.0.0</modelVersion> <groupId>NamedQuery</groupId> <artifactId>NamedQuery</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>NamedQuery</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>5.2.6.Final</version> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>6.0.5</version> </dependency> </dependencies> </project>
Step 3
Create Employee class
- package com.kb.model;
- import javax.persistence.Column;
- import javax.persistence.Entity;
- import javax.persistence.GeneratedValue;
- import javax.persistence.GenerationType;
- import javax.persistence.Id;
- import javax.persistence.NamedNativeQuery;
- import javax.persistence.NamedQueries;
- import javax.persistence.NamedQuery;
- import javax.persistence.Table;
- @Entity
- @Table(name = "Employee")
- @NamedQuery(name = "hql_employee_select", query = "from Employee where age=:age")
- @NamedNativeQuery(name = "sql_employee_select", query = "select * from Employee")
- public class Employee {
- @Id
- @GeneratedValue(strategy = GenerationType.SEQUENCE)
- @Column(name = "Employee_Id")
- private int employeeId;
- @Column(name = "FirstName")
- private String firstName;
- @Column(name = "LastName")
- private String lastName;
- @Column(name = "Age")
- private int age;
- @Column(name = "Education")
- private String education;
- @Column(name = "Salary")
- private int salary;
- public int getEmployeeId() {
- return employeeId;
- }
- public void setEmployeeId(int employeeId) {
- this.employeeId = employeeId;
- }
- public String getFirstName() {
- return firstName;
- }
- public void setFirstName(String firstName) {
- this.firstName = firstName;
- }
- public String getLastName() {
- return lastName;
- }
- public void setLastName(String lastName) {
- this.lastName = lastName;
- }
- public int getAge() {
- return age;
- }
- public void setAge(int age) {
- this.age = age;
- }
- public String getEducation() {
- return education;
- }
- public void setEducation(String education) {
- this.education = education;
- }
- public int getSalary() {
- return salary;
- }
- public void setSalary(int salary) {
- this.salary = salary;
- }
- @Override
- public String toString() {
- StringBuilder sb = new StringBuilder();
- sb.append("Id:").append(employeeId).append(" FirstName:").append(firstName).append("
- Age:").append(age);
- return sb.toString();
- }
- }
package com.kb.model; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.NamedNativeQuery; import javax.persistence.NamedQueries; import javax.persistence.NamedQuery; import javax.persistence.Table; @Entity @Table(name = "Employee") @NamedQuery(name = "hql_employee_select", query = "from Employee where age=:age") @NamedNativeQuery(name = "sql_employee_select", query = "select * from Employee") public class Employee { @Id @GeneratedValue(strategy = GenerationType.SEQUENCE) @Column(name = "Employee_Id") private int employeeId; @Column(name = "FirstName") private String firstName; @Column(name = "LastName") private String lastName; @Column(name = "Age") private int age; @Column(name = "Education") private String education; @Column(name = "Salary") private int salary; public int getEmployeeId() { return employeeId; } public void setEmployeeId(int employeeId) { this.employeeId = employeeId; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getEducation() { return education; } public void setEducation(String education) { this.education = education; } public int getSalary() { return salary; } public void setSalary(int salary) { this.salary = salary; } @Override public String toString() { StringBuilder sb = new StringBuilder(); sb.append("Id:").append(employeeId).append(" FirstName:").append(firstName).append(" Age:").append(age); return sb.toString(); } }
We have defined 2 named queries using @NamedQuery and @NamedNativeQuery annotation in the above class.
@NamedQuery is used to define HQL query.
@NamedNativeQuery is used to define Native SQL query.
Step 4
Create Person class
- package com.kb.model;
- public class Person {
- private int personId;
- private String firstName;
- private String lastName;
- private int age;
- private String education;
- private int salary;
- public int getPersonId() {
- return personId;
- }
- public void setPersonId(int personId) {
- this.personId = personId;
- }
- public String getFirstName() {
- return firstName;
- }
- public void setFirstName(String firstName) {
- this.firstName = firstName;
- }
- public String getLastName() {
- return lastName;
- }
- public void setLastName(String lastName) {
- this.lastName = lastName;
- }
- public int getAge() {
- return age;
- }
- public void setAge(int age) {
- this.age = age;
- }
- public String getEducation() {
- return education;
- }
- public void setEducation(String education) {
- this.education = education;
- }
- public int getSalary() {
- return salary;
- }
- public void setSalary(int salary) {
- this.salary = salary;
- }
- @Override
- public String toString() {
- StringBuilder sb = new StringBuilder();
- sb.append("Id:").append(personId).append(" FirstName:").append(firstName).append("
- Age:").append(age);
- return sb.toString();
- }
- }
package com.kb.model; public class Person { private int personId; private String firstName; private String lastName; private int age; private String education; private int salary; public int getPersonId() { return personId; } public void setPersonId(int personId) { this.personId = personId; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getEducation() { return education; } public void setEducation(String education) { this.education = education; } public int getSalary() { return salary; } public void setSalary(int salary) { this.salary = salary; } @Override public String toString() { StringBuilder sb = new StringBuilder(); sb.append("Id:").append(personId).append(" FirstName:").append(firstName).append(" Age:").append(age); return sb.toString(); } }
Step 5
Create person.hbm.xml
- <?xml version='1.0' encoding='UTF-8'?>
- <!DOCTYPE hibernate-mapping PUBLIC
- "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
- "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
- <hibernate-mapping package="com.kb.model">
- <class name="Person" table="Person">
- <id name="personId" type="int">
- <column name="Person_Id"></column>
- <generator class="increment"></generator>
- </id>
- <property name="firstName" column="FirstName"></property>
- <property name="lastName" column="LastName"></property>
- <property name="age" type="int" column="Age"></property>
- <property name="education" column="Education"></property>
- <property name="salary" type="int" column="Salary"></property>
- </class>
- <query name="hql_person_select">from Person where age=:age</query>
- <sql-query name="sql_person_select">select * from Person
- </sql-query>
- </hibernate-mapping>
<?xml version='1.0' encoding='UTF-8'?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.kb.model"> <class name="Person" table="Person"> <id name="personId" type="int"> <column name="Person_Id"></column> <generator class="increment"></generator> </id> <property name="firstName" column="FirstName"></property> <property name="lastName" column="LastName"></property> <property name="age" type="int" column="Age"></property> <property name="education" column="Education"></property> <property name="salary" type="int" column="Salary"></property> </class> <query name="hql_person_select">from Person where age=:age</query> <sql-query name="sql_person_select">select * from Person </sql-query> </hibernate-mapping>
We have defined 2 named queries in this mapping file where first one is HQL and second one is Native SQL query.
Step 6
Create hibernate.cfg.xml
- <?xml version="1.0" encoding="UTF-8"?>
- <!DOCTYPE hibernate-configuration PUBLIC
- "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
- "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
- <hibernate-configuration>
- <session-factory>
- <!-- Database connection properties -->
- <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
- <property name="connection.url">jdbc:mysql://localhost/javainsimpleway</property>
- <property name="connection.username">root</property>
- <property name="connection.password">root</property>
- <!-- JDBC connection pool (using the built-in) -->
- <property name="connection.pool_size">100</property>
- <!-- SQL dialect -->
- <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
- <!-- Disable the second-level cache -->
- <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
- <!-- Echo all executed SQL to stdout -->
- <property name="show_sql">false</property>
- <!-- Format the generated Sql -->
- <property name="format_sql">false</property>
- <!-- Dont Drop and re-create the database schema on startup,Just update
- it -->
- <property name="hbm2ddl.auto">update</property>
- <mapping class="com.kb.model.Employee" />
- <mapping resource="com/kb/mapping/person.hbm.xml"/>
- </session-factory>
- </hibernate-configuration>
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- Database connection properties --> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost/javainsimpleway</property> <property name="connection.username">root</property> <property name="connection.password">root</property> <!-- JDBC connection pool (using the built-in) --> <property name="connection.pool_size">100</property> <!-- SQL dialect --> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <!-- Disable the second-level cache --> <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property> <!-- Echo all executed SQL to stdout --> <property name="show_sql">false</property> <!-- Format the generated Sql --> <property name="format_sql">false</property> <!-- Dont Drop and re-create the database schema on startup,Just update it --> <property name="hbm2ddl.auto">update</property> <mapping class="com.kb.model.Employee" /> <mapping resource="com/kb/mapping/person.hbm.xml"/> </session-factory> </hibernate-configuration>
We have added both annotation and XML mapping file location in the above config file.
Step 7
Create Hibernate util class
- package com.kb.util;
- import org.hibernate.SessionFactory;
- import org.hibernate.cfg.Configuration;
- public class HibernateUtil {
- private static final SessionFactory sessionFactory = buildSessionFactory();
- private static SessionFactory buildSessionFactory() {
- try {
- // Create the SessionFactory from hibernate.cfg.xml
- return new Configuration().configure().buildSessionFactory();
- } catch (Throwable ex) {
- // Make sure you log the exception to track it
- System.err.println("SessionFactory creation failed." + ex);
- throw new ExceptionInInitializerError(ex);
- }
- }
- public static SessionFactory getSessionFactory() {
- return sessionFactory;
- }
- public static void shutdown() {
- // Optional but can be used to Close caches and connection pools
- getSessionFactory().close();
- }
- }
package com.kb.util; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; public class HibernateUtil { private static final SessionFactory sessionFactory = buildSessionFactory(); private static SessionFactory buildSessionFactory() { try { // Create the SessionFactory from hibernate.cfg.xml return new Configuration().configure().buildSessionFactory(); } catch (Throwable ex) { // Make sure you log the exception to track it System.err.println("SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex); } } public static SessionFactory getSessionFactory() { return sessionFactory; } public static void shutdown() { // Optional but can be used to Close caches and connection pools getSessionFactory().close(); } }
Step 8
Create PopulateData.java file to Populate Employee Table with initial data
- package com.kb.db;
- import org.hibernate.Session;
- import org.hibernate.SessionFactory;
- import org.hibernate.Transaction;
- import com.kb.model.Employee;
- import com.kb.model.Person;
- import com.kb.util.HibernateUtil;
- public class PopulateData {
- public static void main(String[] args) {
- // Get session factory using Hibernate Util class
- SessionFactory sf = HibernateUtil.getSessionFactory();
- // Get session from Sesson factory
- Session session = sf.openSession();
- // Begin transaction
- Transaction t = session.beginTransaction();
- // Create Employee data
- Employee employee1 = new Employee();
- employee1.setFirstName("John");
- employee1.setLastName("KC");
- employee1.setAge(28);
- employee1.setEducation("PG");
- employee1.setSalary(25000);
- Employee employee2 = new Employee();
- employee2.setFirstName("Jacob");
- employee2.setLastName("JC");
- employee2.setAge(28);
- employee2.setEducation("PG");
- employee2.setSalary(30000);
- Employee employee3 = new Employee();
- employee3.setFirstName("Martin");
- employee3.setLastName("A");
- employee3.setAge(24);
- employee3.setEducation("UG");
- employee3.setSalary(20000);
- // Create Person data
- Person Person1 = new Person();
- Person1.setFirstName("Peter");
- Person1.setLastName("M");
- Person1.setAge(28);
- Person1.setEducation("UG");
- Person1.setSalary(22000);
- Person Person2 = new Person();
- Person2.setFirstName("Roshan");
- Person2.setLastName("B");
- Person2.setAge(28);
- Person2.setEducation("PG");
- Person2.setSalary(45000);
- session.save(employee1);
- session.save(employee2);
- session.save(employee3);
- session.save(Person1);
- session.save(Person2);
- // Commit the transaction and close the session
- t.commit();
- session.close();
- System.out.println("successfully persisted Employee and Person details");
- }
- }
package com.kb.db; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import com.kb.model.Employee; import com.kb.model.Person; import com.kb.util.HibernateUtil; public class PopulateData { public static void main(String[] args) { // Get session factory using Hibernate Util class SessionFactory sf = HibernateUtil.getSessionFactory(); // Get session from Sesson factory Session session = sf.openSession(); // Begin transaction Transaction t = session.beginTransaction(); // Create Employee data Employee employee1 = new Employee(); employee1.setFirstName("John"); employee1.setLastName("KC"); employee1.setAge(28); employee1.setEducation("PG"); employee1.setSalary(25000); Employee employee2 = new Employee(); employee2.setFirstName("Jacob"); employee2.setLastName("JC"); employee2.setAge(28); employee2.setEducation("PG"); employee2.setSalary(30000); Employee employee3 = new Employee(); employee3.setFirstName("Martin"); employee3.setLastName("A"); employee3.setAge(24); employee3.setEducation("UG"); employee3.setSalary(20000); // Create Person data Person Person1 = new Person(); Person1.setFirstName("Peter"); Person1.setLastName("M"); Person1.setAge(28); Person1.setEducation("UG"); Person1.setSalary(22000); Person Person2 = new Person(); Person2.setFirstName("Roshan"); Person2.setLastName("B"); Person2.setAge(28); Person2.setEducation("PG"); Person2.setSalary(45000); session.save(employee1); session.save(employee2); session.save(employee3); session.save(Person1); session.save(Person2); // Commit the transaction and close the session t.commit(); session.close(); System.out.println("successfully persisted Employee and Person details"); } }
We are persisting 3 employees and 2 person records in the above class.
Step 9
Lets Create Main class to access Named queries
- package com.kb.db;
- import java.util.Iterator;
- import java.util.List;
- import javax.persistence.Query;
- import org.hibernate.Session;
- import org.hibernate.SessionFactory;
- import com.kb.model.Employee;
- import com.kb.model.Person;
- import com.kb.util.HibernateUtil;
- public class NamedQuery {
- @SuppressWarnings("deprecation")
- public static void main(String[] args) {
- SessionFactory sf = HibernateUtil.getSessionFactory();
- Session session = sf.openSession();
- //Named query from Annotation mapping
- Query queryHqlEmpSelect = session.getNamedQuery("hql_employee_select");
- queryHqlEmpSelect.setParameter("age", 28);
- List<Employee> empList = queryHqlEmpSelect.getResultList();
- System.out.println("HQL-Number of Employees present with Age 28--> " + empList.size());
- System.out.println("HQL-Employees retrieved");
- for (Employee employee : empList) {
- System.out.println(employee);
- }
- Query querySqlEmpSelect = session.getNamedQuery("sql_employee_select");
- List empListSql = querySqlEmpSelect.getResultList();
- System.out.println("SQL-Number of Employees present--> " + empListSql.size());
- System.out.println("SQL-Employees retrieved");
- Iterator iterator1 = empListSql.iterator();
- while (iterator1.hasNext()) {
- Object[] object = (Object[]) iterator1.next();
- System.out.println("EmployeeId : " + object[0] + " Age : " + object[1]
- + " Education : " + object[2]);
- }
- /* for (Employee employee : empList) {
- System.out.println(employee);
- }*/
- //Named query from XML mapping
- Query queryHqlPersonSelect = session.getNamedQuery("hql_person_select");
- queryHqlPersonSelect.setParameter("age", 28);
- List<Person> personList = queryHqlPersonSelect.getResultList();
- System.out.println("HQL-Number of Persons present with Age 28--> " + personList.size());
- System.out.println("HQL-Persons retrieved");
- for (Person person : personList) {
- System.out.println(person);
- }
- Query querySqlPersonSelect = session.getNamedQuery("sql_person_select");
- personList = querySqlPersonSelect.getResultList();
- System.out.println("SQL-Number of Persons present--> " + personList.size());
- System.out.println("SQL-Persons retrieved");
- Iterator iterator2 = personList.iterator();
- while (iterator2.hasNext()) {
- Object[] object = (Object[]) iterator2.next();
- System.out.println("PersonId : " + object[0] + " Age : " + object[3]
- + " Education : " + object[4]);
- }
- session.close();
- }
- }
package com.kb.db; import java.util.Iterator; import java.util.List; import javax.persistence.Query; import org.hibernate.Session; import org.hibernate.SessionFactory; import com.kb.model.Employee; import com.kb.model.Person; import com.kb.util.HibernateUtil; public class NamedQuery { @SuppressWarnings("deprecation") public static void main(String[] args) { SessionFactory sf = HibernateUtil.getSessionFactory(); Session session = sf.openSession(); //Named query from Annotation mapping Query queryHqlEmpSelect = session.getNamedQuery("hql_employee_select"); queryHqlEmpSelect.setParameter("age", 28); List<Employee> empList = queryHqlEmpSelect.getResultList(); System.out.println("HQL-Number of Employees present with Age 28--> " + empList.size()); System.out.println("HQL-Employees retrieved"); for (Employee employee : empList) { System.out.println(employee); } Query querySqlEmpSelect = session.getNamedQuery("sql_employee_select"); List empListSql = querySqlEmpSelect.getResultList(); System.out.println("SQL-Number of Employees present--> " + empListSql.size()); System.out.println("SQL-Employees retrieved"); Iterator iterator1 = empListSql.iterator(); while (iterator1.hasNext()) { Object[] object = (Object[]) iterator1.next(); System.out.println("EmployeeId : " + object[0] + " Age : " + object[1] + " Education : " + object[2]); } /* for (Employee employee : empList) { System.out.println(employee); }*/ //Named query from XML mapping Query queryHqlPersonSelect = session.getNamedQuery("hql_person_select"); queryHqlPersonSelect.setParameter("age", 28); List<Person> personList = queryHqlPersonSelect.getResultList(); System.out.println("HQL-Number of Persons present with Age 28--> " + personList.size()); System.out.println("HQL-Persons retrieved"); for (Person person : personList) { System.out.println(person); } Query querySqlPersonSelect = session.getNamedQuery("sql_person_select"); personList = querySqlPersonSelect.getResultList(); System.out.println("SQL-Number of Persons present--> " + personList.size()); System.out.println("SQL-Persons retrieved"); Iterator iterator2 = personList.iterator(); while (iterator2.hasNext()) { Object[] object = (Object[]) iterator2.next(); System.out.println("PersonId : " + object[0] + " Age : " + object[3] + " Education : " + object[4]); } session.close(); } }
We have accessed HQL and SQL queries defined in both Annotation and XML mapping and executing those queries in the above class.
Step 10
Run PopulateData.java class to create the initial data
Check an output in MYSQL DB
E:\MySql_Install\bin
Mysql –u root –p
Enter password
Use javainsimpleway;
Select * from Employee;
Select * from Person;
We can see that Emploeyee table has 3 records and Person table has 2 records
Step 11
Run the main class NamedQuery.java to check the output of Named queries
Output
We can see that both Person and Employee records are retrieved using HQL and SQL Named queries.