MySQL和Spring Boot

Question

I have a project am working on.it contains four java files including two repositories and a task file.I use the first repository to get user ids and forum ids from a mysql data table with the help of a query and the second repository to check if the user ids and forum ids are already included in a second mySQL database table also using a query . What I don't know is how to insert the user id s and forum ids to the second table if its not already there,using the task.java file. Below are the query's in the repositories.

//1st repository
@query("select t from UserTestSummary t where forumid is not null")
List<UserTestSummary>FindbyId();

//2nd repository
@query("select f from followedforum f")
List<FollowedForum>findbyid();

Answer 1

For sure you could do this with a query in a repository using @Query annotation.

But I personally would implement a service, that uses the repositories, like this :

1. create a service 'SecondService'

2. There create a method SecondService.insertIfNotExist(Long userId,Long forumId), there (pseudo code):

   if(!userRepository.exists(userId)&&!forumRepository.exists(forumId){ secondEntity=new SecondEntity(...) secondRepository.save(secondEntity) }