Database foreign key constrains with cascade on delete

-- Remove elements not following foreign key constaints
DELETE from dbo.User_Release where userId NOT IN (SELECT id from dbo.releaseUser)
DELETE from dbo.Comment where dbo.Comment.releaseId NOT IN (SELECT id from dbo.Release)
DELETE from dbo.User_Release where releaseId NOT IN (SELECT id from dbo.Release)

-- User release
ALTER TABLE User_Release
ADD FOREIGN KEY (userId)
REFERENCES releaseUser(id)
ON DELETE CASCADE;

ALTER TABLE User_Release
ADD FOREIGN KEY (releaseId)
REFERENCES Release(id)
ON DELETE CASCADE;

-- Release
ALTER TABLE Release
ADD FOREIGN KEY (categoryId)
REFERENCES Category(id)
ON DELETE SET NULL;

ALTER TABLE Release
ADD FOREIGN KEY (userId_Owner)
REFERENCES releaseUser(id)
ON DELETE SET NULL;

-- Comment
ALTER TABLE Comment
ADD FOREIGN KEY (releaseId)
REFERENCES Release(id)
ON DELETE CASCADE;

ALTER TABLE Comment
ADD FOREIGN KEY (userId)
REFERENCES releaseUser(id)
ON DELETE CASCADE;

ALTER TABLE Comment
ADD FOREIGN KEY (commentId_Reply)
REFERENCES Comment(id)
ON DELETE CASCADE;