How to Configure Multiple Data Sources in a Spring Boot?

In this post, We will learn How to Configure Multiple Data Sources in a Spring Boot using a demo project?

There are many situations where we need to read/write data from multiple databases and while using Spring data JPA sometimes it becomes challenging to configure to get connections with multiple databases in a single application. Hence, in this post, we are going to discuss creating multiple database connections with Spring data JPA using spring boot through a single application. Actually, spring boot usually provides a very easy way to use multiple data sources in a single application using properties file configurations.

Here We are going to learn How to use MySQL and Oracle databases to get connections in a single Spring Boot application.

Below is the Project Structure created in STS(Spring Tool Suite):

pom.xml

Maven pom with Spring data JPA,mysql-connector-java, and ojdbc8(for Oracle) dependencies.

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.5.2</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.kkhindigyan.app</groupId>
	<artifactId>SpringBootDataJPAWithMultipleDatabaseExample</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>SpringBootDataJPAWithMultipleDatabaseExample</name>
	<description>Demo project for Spring Boot</description>
	<properties>
		<java.version>1.8</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-jpa</artifactId>
		</dependency>

		<dependency>
			<groupId>com.oracle.database.jdbc</groupId>
			<artifactId>ojdbc8</artifactId>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

</parent>

<groupId>com.kkhindigyan.app</groupId>

<artifactId>SpringBootDataJPAWithMultipleDatabaseExample</artifactId>

<version>0.0.1-SNAPSHOT</version>

<name>SpringBootDataJPAWithMultipleDatabaseExample</name>

<description>Demo project for Spring Boot</description>

<java.version>1.8</java.version>

</properties>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-data-jpa</artifactId>

</dependency>

<groupId>com.oracle.database.jdbc</groupId>

<artifactId>ojdbc8</artifactId>

<scope>runtime</scope>

</dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

<scope>runtime</scope>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-test</artifactId>

</dependency>

</dependencies>

<build>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</plugin>

</plugins>

</build>

</project>

We have two different config files (MySQLDBConfig & OracleDBConfig) for two different data sources.

Following is the configuration to connect to MySQL database. We have configured the entitymanager required to query the MySQL database as per JPA.

@ConfigurationProperties(prefix = “spring.mysql.datasource”). This will ensure that spring picks properties starting with spring.mysql.datasource creating the data source and utilizes it while executing methods of UserRepository.java.

basePackages = “com.kkhindigyan.app.user.dao” will ensure that spring uses mysql datasource while executing methods of UserRepository.java

@Primary This annotation tells spring to use this bean to use as a primary bean as we have multiple beans for the same return type. To use other beans of the same return type we require to use @Qualifier annotation.

MySQLDBConfig.java

package com.kkhindigyan.app.config;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.stream.Collectors;

import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PropertiesLoaderUtils;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(entityManagerFactoryRef = "mysqlEntityManager",
transactionManagerRef = "mysqlTransactionManager", basePackages = "com.kkhindigyan.app.user.dao")
public class MySQLDBConfig {

	@Primary
	@Bean
	@ConfigurationProperties(prefix = "spring.mysql.datasource")
	public DataSource mysqlDataSource() {
		return DataSourceBuilder.create().build();
	}

	@Primary
	@Bean(name = "mysqlEntityManager")
	public LocalContainerEntityManagerFactoryBean mysqlEntityManagerFactory(EntityManagerFactoryBuilder builder) {
		return builder.dataSource(mysqlDataSource()).properties(setHibernateProperties())
				.packages("com.kkhindigyan.app.user.entities").build();
	}

	@Primary
	@Bean(name = "mysqlTransactionManager")
	public PlatformTransactionManager mysqlTransactionManager(
			@Qualifier("mysqlEntityManager") EntityManagerFactory entityManagerFactory) {
		return new JpaTransactionManager(entityManagerFactory);
	}

	private Map<String, Object> setHibernateProperties() {
		Resource resource = new ClassPathResource("hibernate.properties");
		try {
			Properties properties = PropertiesLoaderUtils.loadProperties(resource);
			Map<String, Object> propsMap = properties.entrySet().stream()
					.collect(Collectors.toMap(e -> e.getKey().toString(), e -> e.getValue()));
					
			return propsMap;
		} catch (IOException e) {
			return new HashMap<String, Object>();
		}
	}
}

package com.kkhindigyan.app.config;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import java.util.Properties;

import java.util.stream.Collectors;

import javax.persistence.EntityManagerFactory;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Qualifier;

import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.boot.jdbc.DataSourceBuilder;

import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.Primary;

import org.springframework.core.io.ClassPathResource;

import org.springframework.core.io.Resource;

import org.springframework.core.io.support.PropertiesLoaderUtils;

import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

import org.springframework.orm.jpa.JpaTransactionManager;

import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;

import org.springframework.transaction.PlatformTransactionManager;

import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration

@EnableTransactionManagement

@EnableJpaRepositories(entityManagerFactoryRef = "mysqlEntityManager",

transactionManagerRef = "mysqlTransactionManager", basePackages = "com.kkhindigyan.app.user.dao")

public class MySQLDBConfig {

@Primary

@Bean

@ConfigurationProperties(prefix = "spring.mysql.datasource")

public DataSource mysqlDataSource() {

return DataSourceBuilder.create().build();

}

@Primary

@Bean(name = "mysqlEntityManager")

public LocalContainerEntityManagerFactoryBean mysqlEntityManagerFactory(EntityManagerFactoryBuilder builder) {

return builder.dataSource(mysqlDataSource()).properties(setHibernateProperties())

.packages("com.kkhindigyan.app.user.entities").build();

}

@Primary

@Bean(name = "mysqlTransactionManager")

public PlatformTransactionManager mysqlTransactionManager(

@Qualifier("mysqlEntityManager") EntityManagerFactory entityManagerFactory) {

return new JpaTransactionManager(entityManagerFactory);

}

private Map<String, Object> setHibernateProperties() {

Resource resource = new ClassPathResource("hibernate.properties");

try {

Properties properties = PropertiesLoaderUtils.loadProperties(resource);

Map<String, Object> propsMap = properties.entrySet().stream()

.collect(Collectors.toMap(e -> e.getKey().toString(), e -> e.getValue()));

return propsMap;

} catch (IOException e) {

return new HashMap<String, Object>();

}

OracleDBConfig.java

Following is the configuration for Oracle Database The configurations are similar to MySQLDBConfig.java.

package com.kkhindigyan.app.config;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.stream.Collectors;

import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PropertiesLoaderUtils;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(entityManagerFactoryRef = "oracleEntityManager", 
transactionManagerRef = "oracleTransactionManager", basePackages = "com.kkhindigyan.app.emp.dao")
public class OracleDBConfig {

	@Bean
	@ConfigurationProperties(prefix = "spring.oracle.datasource")
	public DataSource oracleDataSource() {
		return DataSourceBuilder.create().build();
	}

	@Bean(name = "oracleEntityManager")
	public LocalContainerEntityManagerFactoryBean oracleEntityManagerFactory(EntityManagerFactoryBuilder builder) {
		return builder.dataSource(oracleDataSource()).properties(setHibernateProperties())
				.packages("com.kkhindigyan.app.employee.entities")
				.build();
	}

	@Bean(name = "oracleTransactionManager")
	public PlatformTransactionManager oracleTransactionManager(
			@Qualifier("oracleEntityManager") EntityManagerFactory entityManagerFactory) {
		return new JpaTransactionManager(entityManagerFactory);
	}

	private Map<String, Object> setHibernateProperties() {
		Resource resource = new ClassPathResource("hibernate.properties");
		try {
			Properties properties = PropertiesLoaderUtils.loadProperties(resource);
			
			Map<String, Object> propsMap = properties.entrySet().stream()
			.collect(Collectors.toMap(e -> e.getKey().toString(), e -> e.getValue()));
			
			return propsMap;
		} catch (IOException e) {
			return new HashMap<String, Object>();
		}
	}

}

package com.kkhindigyan.app.config;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import java.util.Properties;

import java.util.stream.Collectors;

import javax.persistence.EntityManagerFactory;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Qualifier;

import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.boot.jdbc.DataSourceBuilder;

import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.core.io.ClassPathResource;

import org.springframework.core.io.Resource;

import org.springframework.core.io.support.PropertiesLoaderUtils;

import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

import org.springframework.orm.jpa.JpaTransactionManager;

import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;

import org.springframework.transaction.PlatformTransactionManager;

import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration

@EnableTransactionManagement

@EnableJpaRepositories(entityManagerFactoryRef = "oracleEntityManager",

transactionManagerRef = "oracleTransactionManager", basePackages = "com.kkhindigyan.app.emp.dao")

public class OracleDBConfig {

@Bean

@ConfigurationProperties(prefix = "spring.oracle.datasource")

public DataSource oracleDataSource() {

return DataSourceBuilder.create().build();

}

@Bean(name = "oracleEntityManager")

public LocalContainerEntityManagerFactoryBean oracleEntityManagerFactory(EntityManagerFactoryBuilder builder) {

return builder.dataSource(oracleDataSource()).properties(setHibernateProperties())

.packages("com.kkhindigyan.app.employee.entities")

.build();

}

@Bean(name = "oracleTransactionManager")

public PlatformTransactionManager oracleTransactionManager(

@Qualifier("oracleEntityManager") EntityManagerFactory entityManagerFactory) {

return new JpaTransactionManager(entityManagerFactory);

}

private Map<String, Object> setHibernateProperties() {

Resource resource = new ClassPathResource("hibernate.properties");

try {

Properties properties = PropertiesLoaderUtils.loadProperties(resource);

Map<String, Object> propsMap = properties.entrySet().stream()

.collect(Collectors.toMap(e -> e.getKey().toString(), e -> e.getValue()));

return propsMap;

} catch (IOException e) {

return new HashMap<String, Object>();

}

Employee.java

Employee JPA Entity class

package com.kkhindigyan.app.employee.entities;

import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import org.hibernate.annotations.DynamicUpdate;
 
@Entity
@Table(name="employee_table")
@DynamicUpdate
public class Employee {
 
	@Id
	@Column(name="employee_id")
	@GeneratedValue(strategy=GenerationType.AUTO)
	private Integer employeeId;
	
	@Column(name="employee_name",length=100,nullable=false)
	private String employeeName;
	
	@Column(name="email",unique=true)
	private String email;
	
	@Column(name="date_of_joing")
	private Date doj;
	
	@Column(name="salary")
	private Double salary;
	
	public Integer getEmployeeId() {
		return employeeId;
	}
	public void setEmployeeId(Integer employeeId) {
		this.employeeId = employeeId;
	}
	public String getEmployeeName() {
		return employeeName;
	}
	public void setEmployeeName(String employeeName) {
		this.employeeName = employeeName;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public Date getDoj() {
		return doj;
	}
	public void setDoj(Date doj) {
		this.doj = doj;
	}
	public Double getSalary() {
		return salary;
	}
	public void setSalary(Double salary) {
		this.salary = salary;
	}
	@Override
	public String toString() {
		return "Employee [employeeId=" + employeeId + ", employeeName=" + employeeName + ", email=" + email + ", doj="
				+ doj + ", salary=" + salary + "]";
	}
}

package com.kkhindigyan.app.employee.entities;

import java.util.Date;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.Table;

import org.hibernate.annotations.DynamicUpdate;

@Entity

@Table(name="employee_table")

@DynamicUpdate

public class Employee {

@Id

@Column(name="employee_id")

@GeneratedValue(strategy=GenerationType.AUTO)

private Integer employeeId;

@Column(name="employee_name",length=100,nullable=false)

private String employeeName;

@Column(name="email",unique=true)

private String email;

@Column(name="date_of_joing")

private Date doj;

@Column(name="salary")

private Double salary;

public Integer getEmployeeId() {

return employeeId;

}

public void setEmployeeId(Integer employeeId) {

this.employeeId = employeeId;

}

public String getEmployeeName() {

return employeeName;

}

public void setEmployeeName(String employeeName) {

this.employeeName = employeeName;

}

public String getEmail() {

return email;

}

public void setEmail(String email) {

this.email = email;

}

public Date getDoj() {

return doj;

}

public void setDoj(Date doj) {

this.doj = doj;

}

public Double getSalary() {

return salary;

}

public void setSalary(Double salary) {

this.salary = salary;

}

@Override

public String toString() {

return "Employee [employeeId=" + employeeId + ", employeeName=" + employeeName + ", email=" + email + ", doj="

+ doj + ", salary=" + salary + "]";

}

User.java

User JPA Entity class

package com.kkhindigyan.app.user.entities;

import java.time.LocalDate;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import org.hibernate.annotations.DynamicUpdate;

@Entity
@Table(name = "user_table")
@DynamicUpdate
public class User {
	
	@Id
	@Column(name = "id")
	@GeneratedValue(strategy = GenerationType.AUTO)
	private Integer id;
	
	@Column(name = "name")
	private String name;
	
	@Column(name = "age")
	private Integer age;
	
	@Column(name = "date_of_birth")
	private LocalDate dob;

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Integer getAge() {
		return age;
	}

	public void setAge(Integer age) {
		this.age = age;
	}

	public LocalDate getDob() {
		return dob;
	}

	public void setDob(LocalDate dob) {
		this.dob = dob;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + ", age=" + age + ", dob=" + dob + "]";
	}
}

package com.kkhindigyan.app.user.entities;

import java.time.LocalDate;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.Table;

import org.hibernate.annotations.DynamicUpdate;

@Entity

@Table(name = "user_table")

@DynamicUpdate

public class User {

@Id

@Column(name = "id")

@GeneratedValue(strategy = GenerationType.AUTO)

private Integer id;

@Column(name = "name")

private String name;

@Column(name = "age")

private Integer age;

@Column(name = "date_of_birth")

private LocalDate dob;

public Integer getId() {

return id;

}

public void setId(Integer id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public Integer getAge() {

return age;

}

public void setAge(Integer age) {

this.age = age;

}

public LocalDate getDob() {

return dob;

}

public void setDob(LocalDate dob) {

this.dob = dob;

}

@Override

public String toString() {

return "User [id=" + id + ", name=" + name + ", age=" + age + ", dob=" + dob + "]";

}

Following is the DAO interfaces that is responsible to query against MySQL and Oracle databases. Both interfaces(EmployeeRepository & UserRepository) extends CrudRepository which has different CRUD methods such as create, findOne, delete etc.. and hence our DAO’s interfaces automatically inherit them which is available for our service classes to use. It’s spring data that will generate the implementations at run time for these CRUD methods. Hence, we don’t have to provide the implementations.

Notice the generic parameters in CrudRepository. Based on these parameters, Spring data will perform different CRUD operations at run time on our behalf.

EmployeeRepository.java

package com.kkhindigyan.app.emp.dao;

import org.springframework.data.repository.CrudRepository;

import com.kkhindigyan.app.employee.entities.Employee;

public interface EmployeeRepository extends CrudRepository<Employee, Integer> {

}

package com.kkhindigyan.app.emp.dao;

import org.springframework.data.repository.CrudRepository;

import com.kkhindigyan.app.employee.entities.Employee;

public interface EmployeeRepository extends CrudRepository<Employee, Integer> {

}

UserRepository.java

package com.kkhindigyan.app.user.dao;

import org.springframework.data.repository.CrudRepository;

import com.kkhindigyan.app.user.entities.User;

public interface UserRepository extends CrudRepository<User, Integer> {

}

package com.kkhindigyan.app.user.dao;

import org.springframework.data.repository.CrudRepository;

import com.kkhindigyan.app.user.entities.User;

public interface UserRepository extends CrudRepository<User, Integer> {

}

Following are the service classes where we have injected both the DAOs. Here both the service classes communicate with the different DAOs and doing read/write operations from multiple databases.

UserService.java

package com.kkhindigyan.app.user.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.kkhindigyan.app.user.dao.UserRepository;
import com.kkhindigyan.app.user.entities.User;

@Service
public class UserService {

	@Autowired
	private UserRepository userRepository;
	
	public User createUser(User user) {
		return userRepository.save(user);
	}
	
	public Iterable<User> fetchAllUsers(){
		return userRepository.findAll();
	}
}

package com.kkhindigyan.app.user.service;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import com.kkhindigyan.app.user.dao.UserRepository;

import com.kkhindigyan.app.user.entities.User;

@Service

public class UserService {

@Autowired

private UserRepository userRepository;

public User createUser(User user) {

return userRepository.save(user);

}

public Iterable<User> fetchAllUsers(){

return userRepository.findAll();

}

EmployeeService.java

package com.kkhindigyan.app.emp.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.kkhindigyan.app.emp.dao.EmployeeRepository;
import com.kkhindigyan.app.employee.entities.Employee;

@Service
public class EmployeeService {

	@Autowired
	private EmployeeRepository employeeRepository;
	
	public Employee createEmpoyee(Employee employee) {
		return employeeRepository.save(employee);
	}
	
	public Iterable<Employee> fetchAllEmployees(){
		return employeeRepository.findAll();
	}
}

package com.kkhindigyan.app.emp.service;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import com.kkhindigyan.app.emp.dao.EmployeeRepository;

import com.kkhindigyan.app.employee.entities.Employee;

@Service

public class EmployeeService {

@Autowired

private EmployeeRepository employeeRepository;

public Employee createEmpoyee(Employee employee) {

return employeeRepository.save(employee);

}

public Iterable<Employee> fetchAllEmployees(){

return employeeRepository.findAll();

}

Following is the application.properties the file that contains configurations for both MySQL and Oracle databases. You can notice that properties starting from spring.mysql.datasource has MySQL database configuration and properties starting from spring.oracle.data source has Oracle data source configurations. These configurations are used in the above MySQLDBConfig.java & OracleDBConfig.java while configuring entitymanager and transactionmanager for respective database connections.

application.properties

#MySQL Database Configration
spring.mysql.datasource.jdbcUrl=jdbc:mysql://localhost:3306/test
spring.mysql.datasource.username=root
spring.mysql.datasource.password=root
spring.mysql.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

#Orcale Database Configration
spring.oracle.datasource.jdbcUrl=jdbc:oracle:thin:@localhost:1521:ORCL
spring.oracle.datasource.username=SH
spring.oracle.datasource.password=pass123
spring.oracle.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver

spring.jpa.hibernate.ddl-auto=create-drop

#MySQL Database Configration

spring.mysql.datasource.jdbcUrl=jdbc:mysql://localhost:3306/test

spring.mysql.datasource.username=root

spring.mysql.datasource.password=root

spring.mysql.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

#Orcale Database Configration

spring.oracle.datasource.jdbcUrl=jdbc:oracle:thin:@localhost:1521:ORCL

spring.oracle.datasource.username=SH

spring.oracle.datasource.password=pass123

spring.oracle.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver

spring.jpa.hibernate.ddl-auto=create-drop

hibernate.properties

hibernate.show_sql=true
hibernate.format_sql=true
hibernate.hbm2ddl.auto=create

hibernate.show_sql=true

hibernate.format_sql=true

hibernate.hbm2ddl.auto=create

SpringBootDataJpaWithMultipleDatabaseExampleApplication.java

package com.kkhindigyan.app;

import java.time.LocalDate;
import java.time.Month;
import java.util.Date;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

import com.kkhindigyan.app.emp.dao.EmployeeRepository;
import com.kkhindigyan.app.emp.service.EmployeeService;
import com.kkhindigyan.app.employee.entities.Employee;
import com.kkhindigyan.app.user.dao.UserRepository;
import com.kkhindigyan.app.user.entities.User;
import com.kkhindigyan.app.user.service.UserService;

@SpringBootApplication
public class SpringBootDataJpaWithMultipleDatabaseExampleApplication {

	public static void main(String[] args) {
		ConfigurableApplicationContext applicationContext = SpringApplication.run(SpringBootDataJpaWithMultipleDatabaseExampleApplication.class, args);
		
		System.out.println("Creating & Reading User information using MySQL Database..");
		UserService userService = applicationContext.getBean(UserService.class);
		userService.createUser(getUser());
		userService.fetchAllUsers().forEach(System.out::println);
		
		System.out.println("--------------------------------------------------");
	
		System.out.println("Creating & Reading Employee information using Oracle Database..");
		EmployeeService employeeService = applicationContext.getBean(EmployeeService.class);
		employeeService.createEmpoyee(getEmployee());
		employeeService.fetchAllEmployees().forEach(System.out::println);
		
	}
	
	private static Employee getEmployee() {
		Employee employee = new Employee();
		employee.setEmployeeName("Sean");
		employee.setEmail("sean.cs@gmail.com");
		employee.setDoj(new Date());
		employee.setSalary(99000.00);
		return employee;
	}
	
	private static User getUser() {
		User user = new User();
		user.setName("KK");
		user.setAge(32);
		user.setDob(LocalDate.of(1990, Month.DECEMBER, 10));
		return user;
	}
}

package com.kkhindigyan.app;

import java.time.LocalDate;

import java.time.Month;

import java.util.Date;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.context.ConfigurableApplicationContext;

import com.kkhindigyan.app.emp.dao.EmployeeRepository;

import com.kkhindigyan.app.emp.service.EmployeeService;

import com.kkhindigyan.app.employee.entities.Employee;

import com.kkhindigyan.app.user.dao.UserRepository;

import com.kkhindigyan.app.user.entities.User;

import com.kkhindigyan.app.user.service.UserService;

@SpringBootApplication

public class SpringBootDataJpaWithMultipleDatabaseExampleApplication {

public static void main(String[] args) {

ConfigurableApplicationContext applicationContext = SpringApplication.run(SpringBootDataJpaWithMultipleDatabaseExampleApplication.class, args);

System.out.println("Creating & Reading User information using MySQL Database..");

UserService userService = applicationContext.getBean(UserService.class);

userService.createUser(getUser());

userService.fetchAllUsers().forEach(System.out::println);

System.out.println("--------------------------------------------------");

System.out.println("Creating & Reading Employee information using Oracle Database..");

EmployeeService employeeService = applicationContext.getBean(EmployeeService.class);

employeeService.createEmpoyee(getEmployee());

employeeService.fetchAllEmployees().forEach(System.out::println);

}

private static Employee getEmployee() {

Employee employee = new Employee();

employee.setEmployeeName("Sean");

employee.setEmail("[email protected]");

employee.setDoj(new Date());

employee.setSalary(99000.00);

return employee;

}

private static User getUser() {

User user = new User();

user.setName("KK");

user.setAge(32);

user.setDob(LocalDate.of(1990, Month.DECEMBER, 10));

return user;

}

If you run ClientTest.java as Spring Boot App then it will give the below output:

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
[32m :: Spring Boot :: [39m              [2m (v2.5.2)[0;39m

[2m2021-07-17 11:32:31.664[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mpaWithMultipleDatabaseExampleApplication[0;39m [2m:[0;39m Starting SpringBootDataJpaWithMultipleDatabaseExampleApplication using Java 1.8.0_65 on DESKTOP-SJ5V0GM with PID 4816 (D:\JavaWorkSpaces\SpringBootWorkspace_1\SpringBootDataJPAWithMultipleDatabaseExample\target\classes started by Kishan Kumar in D:\JavaWorkSpaces\SpringBootWorkspace_1\SpringBootDataJPAWithMultipleDatabaseExample)
[2m2021-07-17 11:32:31.668[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mpaWithMultipleDatabaseExampleApplication[0;39m [2m:[0;39m No active profile set, falling back to default profiles: default
[2m2021-07-17 11:32:32.008[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36m.s.d.r.c.RepositoryConfigurationDelegate[0;39m [2m:[0;39m Bootstrapping Spring Data JPA repositories in DEFAULT mode.
[2m2021-07-17 11:32:32.046[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36m.s.d.r.c.RepositoryConfigurationDelegate[0;39m [2m:[0;39m Finished Spring Data repository scanning in 30 ms. Found 1 JPA repository interfaces.
[2m2021-07-17 11:32:32.047[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36m.s.d.r.c.RepositoryConfigurationDelegate[0;39m [2m:[0;39m Bootstrapping Spring Data JPA repositories in DEFAULT mode.
[2m2021-07-17 11:32:32.051[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36m.s.d.r.c.RepositoryConfigurationDelegate[0;39m [2m:[0;39m Finished Spring Data repository scanning in 3 ms. Found 1 JPA repository interfaces.
[2m2021-07-17 11:32:32.454[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mo.hibernate.jpa.internal.util.LogHelper [0;39m [2m:[0;39m HHH000204: Processing PersistenceUnitInfo [name: default]
[2m2021-07-17 11:32:32.496[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36morg.hibernate.Version                   [0;39m [2m:[0;39m HHH000412: Hibernate ORM core version 5.4.32.Final
[2m2021-07-17 11:32:32.498[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36morg.hibernate.cfg.Environment           [0;39m [2m:[0;39m HHH000205: Loaded properties from resource hibernate.properties: {hibernate.show_sql=true, hibernate.bytecode.use_reflection_optimizer=false, hibernate.hbm2ddl.auto=update, hibernate.format_sql=true}
[2m2021-07-17 11:32:32.622[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mo.hibernate.annotations.common.Version  [0;39m [2m:[0;39m HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
[2m2021-07-17 11:32:32.739[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mcom.zaxxer.hikari.HikariDataSource      [0;39m [2m:[0;39m HikariPool-1 - Starting...
[2m2021-07-17 11:32:32.875[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mcom.zaxxer.hikari.HikariDataSource      [0;39m [2m:[0;39m HikariPool-1 - Start completed.
[2m2021-07-17 11:32:32.901[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36morg.hibernate.dialect.Dialect           [0;39m [2m:[0;39m HHH000400: Using dialect: org.hibernate.dialect.MySQL55Dialect
Hibernate: 
    
    create table hibernate_sequence (
       next_val bigint
    ) engine=InnoDB
Hibernate: 
    
    insert into hibernate_sequence values ( 1 )
Hibernate: 
    
    create table user_table (
       id integer not null,
        age integer,
        date_of_birth date,
        name varchar(255),
        primary key (id)
    ) engine=InnoDB
[2m2021-07-17 11:32:33.429[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mo.h.e.t.j.p.i.JtaPlatformInitiator      [0;39m [2m:[0;39m HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
[2m2021-07-17 11:32:33.437[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mj.LocalContainerEntityManagerFactoryBean[0;39m [2m:[0;39m Initialized JPA EntityManagerFactory for persistence unit 'default'
[2m2021-07-17 11:32:33.451[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mo.hibernate.jpa.internal.util.LogHelper [0;39m [2m:[0;39m HHH000204: Processing PersistenceUnitInfo [name: default]
[2m2021-07-17 11:32:33.457[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mcom.zaxxer.hikari.HikariDataSource      [0;39m [2m:[0;39m HikariPool-2 - Starting...
[2m2021-07-17 11:32:33.457[0;39m [33m WARN[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mcom.zaxxer.hikari.util.DriverDataSource [0;39m [2m:[0;39m Registered driver with driverClassName=oracle.jdbc.driver.OracleDriver was not found, trying direct instantiation.
[2m2021-07-17 11:32:33.829[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mcom.zaxxer.hikari.HikariDataSource      [0;39m [2m:[0;39m HikariPool-2 - Start completed.
[2m2021-07-17 11:32:33.831[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36morg.hibernate.dialect.Dialect           [0;39m [2m:[0;39m HHH000400: Using dialect: org.hibernate.dialect.Oracle10gDialect
Hibernate: 
    
    create table employee_table (
       employee_id number(10,0) not null,
        date_of_joing timestamp,
        email varchar2(255 char),
        employee_name varchar2(100 char) not null,
        salary double precision,
        primary key (employee_id)
    )
Hibernate: 
    
    alter table employee_table 
       drop constraint UK_2casspobvavvi9s23312f9mhm
Hibernate: 
    
    alter table employee_table 
       add constraint UK_2casspobvavvi9s23312f9mhm unique (email)
[2m2021-07-17 11:32:34.247[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mo.h.e.t.j.p.i.JtaPlatformInitiator      [0;39m [2m:[0;39m HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
[2m2021-07-17 11:32:34.247[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mj.LocalContainerEntityManagerFactoryBean[0;39m [2m:[0;39m Initialized JPA EntityManagerFactory for persistence unit 'default'
[2m2021-07-17 11:32:34.518[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[           main][0;39m [36mpaWithMultipleDatabaseExampleApplication[0;39m [2m:[0;39m Started SpringBootDataJpaWithMultipleDatabaseExampleApplication in 3.214 seconds (JVM running for 3.856)
<span style="color: #0000ff;">Creating & Reading User information using MySQL Database..</span>
Hibernate: 
    select
        next_val as id_val 
    from
        hibernate_sequence for update
            
Hibernate: 
    update
        hibernate_sequence 
    set
        next_val= ? 
    where
        next_val=?
Hibernate: 
    insert 
    into
        user_table
        (age, date_of_birth, name, id) 
    values
        (?, ?, ?, ?)
Hibernate: 
    select
        user0_.id as id1_0_,
        user0_.age as age2_0_,
        user0_.date_of_birth as date_of_3_0_,
        user0_.name as name4_0_ 
    from
        user_table user0_
User [id=1, name=KK, age=32, dob=1990-12-10]
--------------------------------------------------
<span style="color: #0000ff;">Creating & Reading Employee information using Oracle Database..</span>
Hibernate: 
    select
        hibernate_sequence.nextval 
    from
        dual
Hibernate: 
    insert 
    into
        employee_table
        (date_of_joing, email, employee_name, salary, employee_id) 
    values
        (?, ?, ?, ?, ?)
Hibernate: 
    select
        employee0_.employee_id as employee_id1_0_,
        employee0_.date_of_joing as date_of_joing2_0_,
        employee0_.email as email3_0_,
        employee0_.employee_name as employee_name4_0_,
        employee0_.salary as salary5_0_ 
    from
        employee_table employee0_
Employee [employeeId=22, employeeName=Sean, email=sean.cs@gmail.com, doj=2021-07-17 11:32:34.683, salary=99000.0]
[2m2021-07-17 11:32:34.909[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mj.LocalContainerEntityManagerFactoryBean[0;39m [2m:[0;39m Closing JPA EntityManagerFactory for persistence unit 'default'
[2m2021-07-17 11:32:34.909[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mcom.zaxxer.hikari.HikariDataSource      [0;39m [2m:[0;39m HikariPool-2 - Shutdown initiated...
[2m2021-07-17 11:32:34.997[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mcom.zaxxer.hikari.HikariDataSource      [0;39m [2m:[0;39m HikariPool-2 - Shutdown completed.
[2m2021-07-17 11:32:34.997[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mj.LocalContainerEntityManagerFactoryBean[0;39m [2m:[0;39m Closing JPA EntityManagerFactory for persistence unit 'default'
[2m2021-07-17 11:32:34.998[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mcom.zaxxer.hikari.HikariDataSource      [0;39m [2m:[0;39m HikariPool-1 - Shutdown initiated...
[2m2021-07-17 11:32:35.002[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mcom.zaxxer.hikari.HikariDataSource      [0;39m [2m:[0;39m HikariPool-1 - Shutdown completed.

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. ____ _ __ _ _

/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

\\/ ___)| |_)| | | | | || (_| | ) ) ) )

' |____| .__|_| |_|_| |_\__, | / / / /

=========|_|==============|___/=/_/_/_/

[32m :: Spring Boot :: [39m [2m (v2.5.2)[0;39m

[2m2021-07-17 11:32:31.664[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mpaWithMultipleDatabaseExampleApplication[0;39m [2m:[0;39m Starting SpringBootDataJpaWithMultipleDatabaseExampleApplication using Java 1.8.0_65 on DESKTOP-SJ5V0GM with PID 4816 (D:\JavaWorkSpaces\SpringBootWorkspace_1\SpringBootDataJPAWithMultipleDatabaseExample\target\classes started by Kishan Kumar in D:\JavaWorkSpaces\SpringBootWorkspace_1\SpringBootDataJPAWithMultipleDatabaseExample)

[2m2021-07-17 11:32:31.668[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mpaWithMultipleDatabaseExampleApplication[0;39m [2m:[0;39m No active profile set, falling back to default profiles: default

[2m2021-07-17 11:32:32.008[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36m.s.d.r.c.RepositoryConfigurationDelegate[0;39m [2m:[0;39m Bootstrapping Spring Data JPA repositories in DEFAULT mode.

[2m2021-07-17 11:32:32.046[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36m.s.d.r.c.RepositoryConfigurationDelegate[0;39m [2m:[0;39m Finished Spring Data repository scanning in 30 ms. Found 1 JPA repository interfaces.

[2m2021-07-17 11:32:32.047[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36m.s.d.r.c.RepositoryConfigurationDelegate[0;39m [2m:[0;39m Bootstrapping Spring Data JPA repositories in DEFAULT mode.

[2m2021-07-17 11:32:32.051[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36m.s.d.r.c.RepositoryConfigurationDelegate[0;39m [2m:[0;39m Finished Spring Data repository scanning in 3 ms. Found 1 JPA repository interfaces.

[2m2021-07-17 11:32:32.454[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mo.hibernate.jpa.internal.util.LogHelper [0;39m [2m:[0;39m HHH000204: Processing PersistenceUnitInfo [name: default]

[2m2021-07-17 11:32:32.496[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36morg.hibernate.Version [0;39m [2m:[0;39m HHH000412: Hibernate ORM core version 5.4.32.Final

[2m2021-07-17 11:32:32.498[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36morg.hibernate.cfg.Environment [0;39m [2m:[0;39m HHH000205: Loaded properties from resource hibernate.properties: {hibernate.show_sql=true, hibernate.bytecode.use_reflection_optimizer=false, hibernate.hbm2ddl.auto=update, hibernate.format_sql=true}

[2m2021-07-17 11:32:32.622[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mo.hibernate.annotations.common.Version [0;39m [2m:[0;39m HCANN000001: Hibernate Commons Annotations {5.1.2.Final}

[2m2021-07-17 11:32:32.739[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mcom.zaxxer.hikari.HikariDataSource [0;39m [2m:[0;39m HikariPool-1 - Starting...

[2m2021-07-17 11:32:32.875[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mcom.zaxxer.hikari.HikariDataSource [0;39m [2m:[0;39m HikariPool-1 - Start completed.

[2m2021-07-17 11:32:32.901[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36morg.hibernate.dialect.Dialect [0;39m [2m:[0;39m HHH000400: Using dialect: org.hibernate.dialect.MySQL55Dialect

Hibernate:

create table hibernate_sequence (

next_val bigint

) engine=InnoDB

Hibernate:

insert into hibernate_sequence values ( 1 )

Hibernate:

create table user_table (

id integer not null,

age integer,

date_of_birth date,

name varchar(255),

primary key (id)

) engine=InnoDB

[2m2021-07-17 11:32:33.429[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mo.h.e.t.j.p.i.JtaPlatformInitiator [0;39m [2m:[0;39m HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]

[2m2021-07-17 11:32:33.437[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mj.LocalContainerEntityManagerFactoryBean[0;39m [2m:[0;39m Initialized JPA EntityManagerFactory for persistence unit 'default'

[2m2021-07-17 11:32:33.451[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mo.hibernate.jpa.internal.util.LogHelper [0;39m [2m:[0;39m HHH000204: Processing PersistenceUnitInfo [name: default]

[2m2021-07-17 11:32:33.457[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mcom.zaxxer.hikari.HikariDataSource [0;39m [2m:[0;39m HikariPool-2 - Starting...

[2m2021-07-17 11:32:33.457[0;39m [33m WARN[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mcom.zaxxer.hikari.util.DriverDataSource [0;39m [2m:[0;39m Registered driver with driverClassName=oracle.jdbc.driver.OracleDriver was not found, trying direct instantiation.

[2m2021-07-17 11:32:33.829[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mcom.zaxxer.hikari.HikariDataSource [0;39m [2m:[0;39m HikariPool-2 - Start completed.

[2m2021-07-17 11:32:33.831[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36morg.hibernate.dialect.Dialect [0;39m [2m:[0;39m HHH000400: Using dialect: org.hibernate.dialect.Oracle10gDialect

Hibernate:

create table employee_table (

employee_id number(10,0) not null,

date_of_joing timestamp,

email varchar2(255 char),

employee_name varchar2(100 char) not null,

salary double precision,

primary key (employee_id)

)

Hibernate:

alter table employee_table

drop constraint UK_2casspobvavvi9s23312f9mhm

Hibernate:

alter table employee_table

add constraint UK_2casspobvavvi9s23312f9mhm unique (email)

[2m2021-07-17 11:32:34.247[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mo.h.e.t.j.p.i.JtaPlatformInitiator [0;39m [2m:[0;39m HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]

[2m2021-07-17 11:32:34.247[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mj.LocalContainerEntityManagerFactoryBean[0;39m [2m:[0;39m Initialized JPA EntityManagerFactory for persistence unit 'default'

[2m2021-07-17 11:32:34.518[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ main][0;39m [36mpaWithMultipleDatabaseExampleApplication[0;39m [2m:[0;39m Started SpringBootDataJpaWithMultipleDatabaseExampleApplication in 3.214 seconds (JVM running for 3.856)

<span style="color: #0000ff;">Creating & Reading User information using MySQL Database..</span>

Hibernate:

select

next_val as id_val

from

hibernate_sequence for update

Hibernate:

update

hibernate_sequence

set

next_val= ?

where

next_val=?

Hibernate:

insert

into

user_table

(age, date_of_birth, name, id)

values

(?, ?, ?, ?)

Hibernate:

select

user0_.id as id1_0_,

user0_.age as age2_0_,

user0_.date_of_birth as date_of_3_0_,

user0_.name as name4_0_

from

user_table user0_

User [id=1, name=KK, age=32, dob=1990-12-10]

--------------------------------------------------

<span style="color: #0000ff;">Creating & Reading Employee information using Oracle Database..</span>

Hibernate:

select

hibernate_sequence.nextval

from

dual

Hibernate:

insert

into

employee_table

(date_of_joing, email, employee_name, salary, employee_id)

values

(?, ?, ?, ?, ?)

Hibernate:

select

employee0_.employee_id as employee_id1_0_,

employee0_.date_of_joing as date_of_joing2_0_,

employee0_.email as email3_0_,

employee0_.employee_name as employee_name4_0_,

employee0_.salary as salary5_0_

from

employee_table employee0_

Employee [employeeId=22, employeeName=Sean, email[email protected], doj=2021-07-17 11:32:34.683, salary=99000.0]

[2m2021-07-17 11:32:34.909[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mj.LocalContainerEntityManagerFactoryBean[0;39m [2m:[0;39m Closing JPA EntityManagerFactory for persistence unit 'default'

[2m2021-07-17 11:32:34.909[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mcom.zaxxer.hikari.HikariDataSource [0;39m [2m:[0;39m HikariPool-2 - Shutdown initiated...

[2m2021-07-17 11:32:34.997[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mcom.zaxxer.hikari.HikariDataSource [0;39m [2m:[0;39m HikariPool-2 - Shutdown completed.

[2m2021-07-17 11:32:34.997[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mj.LocalContainerEntityManagerFactoryBean[0;39m [2m:[0;39m Closing JPA EntityManagerFactory for persistence unit 'default'

[2m2021-07-17 11:32:34.998[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mcom.zaxxer.hikari.HikariDataSource [0;39m [2m:[0;39m HikariPool-1 - Shutdown initiated...

[2m2021-07-17 11:32:35.002[0;39m [32m INFO[0;39m [35m4816[0;39m [2m---[0;39m [2m[ionShutdownHook][0;39m [36mcom.zaxxer.hikari.HikariDataSource [0;39m [2m:[0;39m HikariPool-1 - Shutdown completed.

That’s all about How to Configure Multiple Data Sources in a Spring Boot?

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