SQL Server 2017

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create table users (user_id int primary key);
create table questions(
    question_id int primary key,
    user_id int
);
create table answers(
    answer_id int primary key,
    user_id int 
);
alter table answers add constraint answers_users 
    foreign key(user_id)
    references users(user_id)
    on delete cascade
;
alter table questions add constraint questions_users 
    foreign key(user_id)
    references users(user_id)
    on delete cascade
;
insert into users values (1), (2);
insert into questions values(1, 1), (2, 2);
insert into answers values(1, 1), (2, 2);
6 rows affected

delete from users where user_id = 1;
1 rows affected

select * from questions;


question_id
user_id


2
2


select * from answers;


answer_id
user_id


2
2