Using @AttributeOverrides and @AttributeOverride anotations, we can override the column properties of embedded type.
Example
@Embedded
@AttributeOverrides({
@AttributeOverride( name = "firstName", column = @Column(name = "contact_first_name")),
@AttributeOverride( name = "middleName", column = @Column(name = "contact_middle_name")),
@AttributeOverride( name = "lastName", column = @Column(name = "contact_last_name"))
})
private Name name;
Find the below working application.
Step 1: Create new maven project ‘hibernate-override-embedded-props-demo’.
Step 2: Update pom.xml with maven dependencies.
pom.xml
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.sample.app</groupId>
<artifactId>hibernate-override-embedded-props-demo</artifactId>
<version>1</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>15</java.version>
<maven.compiler.source>${java.version}</maven.compiler.source>
<maven.compiler.target>${java.version}</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>42.4.1</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>6.1.2.Final</version>
</dependency>
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>javax.persistence-api</artifactId>
<version>2.2</version>
</dependency>
</dependencies>
</project>
Step 3: Define Name and Contact classes.
Name.java
package com.sample.app.entity;
import jakarta.persistence.Embeddable;
@Embeddable
public class Name {
private String firstName;
private String middleName;
private String lastName;
public Name() {}
public Name(String firstName, String middleName, String lastName) {
this.firstName = firstName;
this.middleName = middleName;
this.lastName = lastName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getMiddleName() {
return middleName;
}
public void setMiddleName(String middleName) {
this.middleName = middleName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}
Contact.java
package com.sample.app.entity;
import jakarta.persistence.AttributeOverride;
import jakarta.persistence.AttributeOverrides;
import jakarta.persistence.Embedded;
import jakarta.persistence.Entity;
import jakarta.persistence.Id;
import jakarta.persistence.Table;
import jakarta.persistence.Column;
@Entity
@Table(name = "contact")
public class Contact {
@Id
private Integer id;
@Embedded
@AttributeOverrides({
@AttributeOverride( name = "firstName", column = @Column(name = "contact_first_name")),
@AttributeOverride( name = "middleName", column = @Column(name = "contact_middle_name")),
@AttributeOverride( name = "lastName", column = @Column(name = "contact_last_name"))
})
private Name name;
private Integer age;
public Contact(Integer id, Name name, Integer age) {
this.id = id;
this.name = name;
this.age = age;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Name getName() {
return name;
}
public void setName(Name name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
Step 4: Create hibernate.cfg.xml file under src/main/resources folder.
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 settings -->
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="connection.url">jdbc:postgresql://127.0.0.1:5432/test</property>
<property name="connection.username">postgres</property>
<property name="connection.password">postgres</property>
<!-- Enable the logging of all the generated SQL statements to the console -->
<property name="show_sql">true</property>
<!-- Format the generated SQL statement to make it more readable, -->
<property name="format_sql">true</property>
<!-- Hibernate will put comments inside all generated SQL statements to
hint what’s the generated SQL trying to do -->
<property name="use_sql_comments">false</property>
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create</property>
<!-- mappings for annotated classes -->
<mapping class="com.sample.app.entity.Contact" />
</session-factory>
</hibernate-configuration>
Step 5: Define main application class.
App.java
package com.sample.app;
import java.io.IOException;
import java.net.URISyntaxException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import com.sample.app.entity.Contact;
import com.sample.app.entity.Name;
public class App {
private static final SessionFactory SESSION_FACTORY = buildSessionFactory();
private static SessionFactory buildSessionFactory() {
try {
final StandardServiceRegistry standardRegistry = new StandardServiceRegistryBuilder()
.configure("hibernate.cfg.xml").build();
final Metadata metaData = new MetadataSources(standardRegistry).getMetadataBuilder().build();
return metaData.getSessionFactoryBuilder().build();
} catch (Throwable ex) {
throw new ExceptionInInitializerError(ex);
}
}
public static void main(final String args[]) throws ClassNotFoundException, IOException, URISyntaxException {
final Contact contact1 = new Contact(1, new Name("Krishna", null, "G"), 34);
final Contact contact2 = new Contact(2, new Name("Ram", "krishna", "Geeta"), 39);
try (final Session session = SESSION_FACTORY.openSession()) {
session.beginTransaction();
session.persist(contact1);
session.persist(contact2);
session.getTransaction().commit();
}
}
}
Total project structure looks like below.
Run App.java, you will see below messages in the console.
Aug 08, 2022 9:32:52 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate ORM core version 6.1.2.Final
Aug 08, 2022 9:32:52 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using built-in connection pool (not intended for production use)
Aug 08, 2022 9:32:52 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: Loaded JDBC driver class: org.postgresql.Driver
Aug 08, 2022 9:32:52 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001012: Connecting with JDBC URL [jdbc:postgresql://127.0.0.1:5432/test]
Aug 08, 2022 9:32:52 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {password=****, user=postgres}
Aug 08, 2022 9:32:52 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
Aug 08, 2022 9:32:52 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH10001115: Connection pool size: 20 (min=1)
Aug 08, 2022 9:32:52 PM org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl logSelectedDialect
INFO: HHH000400: Using dialect: org.hibernate.dialect.PostgreSQLDialect
Aug 08, 2022 9:32:53 PM org.hibernate.metamodel.internal.EntityInstantiatorPojoStandard resolveConstructor
INFO: HHH000182: No default (no-argument) constructor for class: com.sample.app.entity.Contact (class must be instantiated by Interceptor)
Hibernate:
drop table if exists contact cascade
Aug 08, 2022 9:32:53 PM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@3f183caa] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
Aug 08, 2022 9:32:53 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper$StandardWarningHandler logWarning
WARN: SQL Warning Code: 0, SQLState: 00000
Aug 08, 2022 9:32:53 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper$StandardWarningHandler logWarning
WARN: table "contact" does not exist, skipping
Hibernate:
create table contact (
id integer not null,
age integer,
contact_first_name varchar(255),
contact_last_name varchar(255),
contact_middle_name varchar(255),
primary key (id)
)
Aug 08, 2022 9:32:53 PM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@65383667] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
Aug 08, 2022 9:32:53 PM org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformInitiator initiateService
INFO: HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
Hibernate:
insert
into
contact
(age, contact_first_name, contact_last_name, contact_middle_name, id)
values
(?, ?, ?, ?, ?)
Hibernate:
insert
into
contact
(age, contact_first_name, contact_last_name, contact_middle_name, id)
values
(?, ?, ?, ?, ?)
You can confirm the DDL by querying the PostgreSQL.
test=# \d+ contact
Table "public.contact"
Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
---------------------+------------------------+-----------+----------+---------+----------+-------------+--------------+-------------
id | integer | | not null | | plain | | |
age | integer | | | | plain | | |
contact_first_name | character varying(255) | | | | extended | | |
contact_last_name | character varying(255) | | | | extended | | |
contact_middle_name | character varying(255) | | | | extended | | |
Indexes:
"contact_pkey" PRIMARY KEY, btree (id)
Access method: heap
You can download this application from this link.
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