Is there a standard method for updating data in a JPA repository?

There is no specific standard method for updating data in a JPA repository. The update is performed through the save() method (for example, in Spring Data JPA), which handles both inserting and updating an entity depending on whether a record with the same identifier already exists.

Example:

@Entity
public class User {
    @Id
    private Long id;
    private String name;
    // getters and setters
}

public interface UserRepository extends JpaRepository<User, Long> {}

// Usage
User user = userRepository.findById(1L).orElseThrow();
user.setName("New Name");
userRepository.save(user); // updates the record in the database

Thus, to update data, you need to retrieve the entity, modify the necessary fields, and call save(). JPA will automatically determine that this is an update, not an insert.