Can we use multiple datasource in Spring boot?

Can we use multiple datasource in Spring boot?

So, to use multiple data sources, we need to declare multiple beans with different mappings within Spring’s application context. The configuration for the data sources must look like this: spring: datasource: todos: url: username: …

Is it possible to define multiple transaction manager in Spring?

Most Spring applications need only a single transaction manager, but there may be situations where you want multiple independent transaction managers in a single application. You can use the value attribute of the @Transactional annotation to optionally specify the identity of the PlatformTransactionManager to be used.

How would you configure multiple data sources in a Spring boot application?

Multiple Data Sources with Spring Boot

1. Maven Setup. To set up our Spring Boot project, we need to add spring-boot-starter-data-jpa dependency to the pom.
2. DataSource Configurations.
3. JPA Entities.
4. Package Structure.
5. JPA Repositories.
6. Spring Configuration Classes.
7. Testing.

How can I access multiple databases in Spring boot?

Using multiple datasources with Spring Boot and Spring Data 💈 ⇄🌱 ⇄ 💈

1. Add an additional datasource configuration to your application.properties.
2. Set the SQL Dialect to “default” in your application.properties to let Spring autodetect the different SQL Dialects of each datasource.

How Spring transactions use multiple threads?

The problem arises when we want to manage a transaction across multiple threads. Spring doesn’t support transactions over multiple threads out of the box. Spring doesn’t explicitly mention that in the documentation, but you will end up with runtime errors or unexpected results if you try to do so.

Why do we use @transactional annotation in Spring boot?

The @Transactional annotation makes use of the attributes rollbackFor or rollbackForClassName to rollback the transactions, and the attributes noRollbackFor or noRollbackForClassName to avoid rollback on listed exceptions. The default rollback behavior in the declarative approach will rollback on runtime exceptions.

Is @transactional thread safe?

Spring uses the underlying database implementation for transactions, so they are as thread safe as the underlying database can be.

How are transactions implemented in multi threaded environment?

Your parent processing thread will (1.) create new threads to do parallel DB inserts, (2.) create a CountDownLatch object (this will hold your parent thread until all child threads which are doing db inserts are finished) (3.) create a db connection object with auto commit mode as FALSE.

How does JPA connect to multiple databases in spring boot?

Follow the below steps:

1. Add an additional datasource configuration to your application.
2. Set the SQL Dialect to “default” in your application.
3. Create a Java Package for each datasource with two nested Packages.
4. Create a Configuration Class for the First database.
5. Create a Configuration Class for the Second database.

What is the difference between credit repository and JpaRepository?

Their main functions are: CrudRepository mainly provides CRUD functions. PagingAndSortingRepository provides methods to do pagination and sorting records. JpaRepository provides some JPA-related methods such as flushing the persistence context and deleting records in a batch.

How to connect to multiple datasources with Spring Boot?

However, if you need to connect to multiple datasources with Spring Boot, additional configuration is needed. You need to provide configuration data to Spring Boot, customized for each data source. The source code of our sample application is available on GitHub .

How do we use spring data JPA for data access?

Our application will be using Spring Data JPA for data access through its repository interfaces that abstract us from the EM (Entity Manager). We use the EMF bean to obtain instances of EMs which interact with the JPA entities.

What is the bean definition of a transaction manager?

The bean definition of a transaction manager requires a reference to the entity manager factory bean. We will to use the annotation to auto-wire the entity manager specific to the data source’ s transaction manager.

What is @transactional in JPA?

This means the primary transaction manager will be used by default. This is a JPA respository class used for Product CRUD operations in the secondary database. @Transactional indicates that a transaction is required to execute the update query.