Develop Reference

Is it possible to use memSQL/SingleStore with Spring Data JPA?

I want to use SingleStore database with my Spring Boot Application which uses Spring Data JPA. How it can be achieved?

To leverage SingleStoreDB with Spring Boot, you would use the JDBC connectors for both technologies - Spring + SingleStore. If you are using some ORM style features, use the mysql dialect. If you run into issues you can raise them here, on the forum or to support if you're an active customer.

what is the difference between spring-boot-starter-data-rest and spring-boot-starter-data-jpa

I am trying to understand various dependencies of spring boot.
I have come across three of them:
spring-boot-starter-data-rest
spring-boot-starter-data-jpa
spring-boot-starter-data-jdbc
I would like to know the difference between the three. Tried searching online documents, which say the three are almost related to spring data. how to resolve the confusion?
To add in here I have also found an another dependency
spring-boot-starter-web-services. I think it supports both SOAP and REST. Its just my assumption, I waiting for an explanation

spring-boot-starter-data-jpa is used to access your database with JPA (Java Persistence API)
spring-boot-starter-data-jdbc is used to access your data with jdbc (Java Database Connectivity)
the difference between JPA and JDBC is the level of abstraction. JDBC is more low level, JPA is more 'magic'
and spring-boot-starter-data-rest is used to provide Rest Endpoints on top of your Spring Data repositories.
To do this, you just annotate your spring data repository with a RepositoryRestResource annotation and direct Spring MVC creates the Restful endpoints.
#RepositoryRestResource(collectionResourceRel = "people", path = "people")
public interface PersonRepository extends PagingAndSortingRepository<Person, Long> {
List<Person> findByLastName(#Param("name") String name);
}
This is very handy if you do very CRUD like (Create, Read, Update, Delete) applications.

JPA means "Java Persistence API". It's for querying or saving data in relational databases using object-relational mapping.
REST means "REpresentational State Transfer". It's a style for creating web services that leverages HTTP verbs, a simpler alternative to SOAP.
JDBC starter uses the Spring JdbcTemplate to query or save data in relational databases without relying on object-relational mapping. You write SQL and ask the JdbcTemplate class to execute it in the database using JDBC.
I would say JPA and JDBC starters should be mutually exclusive: either one or the other.
You use REST only if you're writing web services. These may or may not query or persist data in a relational database. I would expect to see both the REST starter and a persistence starter in a pom if a REST service needed persistent data.
Three very different starters.
You ask why Spring Boot has a REST data starter parent that combines the two. In a word: convenience.

How do manage multiiple transaction managers (for multi-tenancy) in Spring Data JPA

We are using Spring Boot with Spring Data JPA with the Transactional annotation for managing transactions.
However, we have a multi-tenant application and for very large customers, we need to put them on a separate dedicated DB.
Is there any way to intercept with TransactionManager is used by the TransactionalAnnotation and dynamically override it per request (depending which tenant is getting updated)?

This is a very useful link for your need, implementing multitenancy in spring boot with spring data Jpa,
It saves the list of tenants in a master(common) database and Hibernate manages the multitenancy datasources (seperate Databases per tenant).

Transactional Support in Spring Data Elastic Search

I am working with Spring Data Elasticsearch , Spring Data has support for Transactional queries .
This i am enabling by #Transactional annotation.
But since elasticsearch does not have any ACID properties what does this Transactional do, the documentation itself is not clear about this

On Spring Data Elasticsearch, it does nothing. It's an annotation from Spring Data Commons, but not all stores support all attributes and features from that.

Can I use Hibernate with JTA?

If JTA is an API, can I use Hibernate as an implementation of JTA?
I have an application with Spring and Hibernate and I wonder which framework should be responsible for transactions, Spring or Hibernate?

Hibernate is not an implementation of JTA. Hibernate is a JPA implementation.
JTA is an enterprise transaction spec, that's implemented by Java EE providers or stand-along transaction managers (e.g. Bitronix).
Hibernate offers a Transaction API abstraction because ORM tools employ a transactional write-behind Persistence Context.
Spring offers a transaction management abstraction, which allows you to switch from RESOURCE_LOCAL to JTA transactions with just some trivial configuration changes.
Spring manages to integrate on top of Hibernate/JPA Transaction API abstraction too.
If you use Spring, then you should take advantage of its transaction management abstraction, and so you don't have to use the Hibernate/JPA Transaction API.
Because Spring uses AOP, the transaction management is decoupled from your business logic, which would not be the case if you were using the programmatic Hibernate/JPA Transaction API.