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Explanation

JPA Query is used to communicate with the database in Java applications using JPA (Java Persistence API). It helps to fetch, insert, update, and delete data.

Code:

@Repository
public interface UserRepository extends 
JpaRepository<User, Long> {

}

Explanation

Method Name Query automatically generates SQL queries based on the method name.

Code:

List<User> findByName(String name);

Explanation

JPQL Query uses entity class names and entity fields instead of database table names.

Code:

@Query("SELECT u FROM User u")
List<User> getAllUsers();

Explanation

Fetch a user using email with JPQL query.

Code:

@Query("SELECT u FROM User u 
WHERE u.email = :email")
User findByEmail(@Param("email") 
String email);

Explanation

Native Query uses actual SQL queries directly.

Code:

@Query(value = "SELECT * FROM users", 
nativeQuery = true)
List<User> getUsers();

Explanation

Insert operation is usually done using save() method provided by JpaRepository.

Code:

userRepository.save(user);