下面两个例子并发访问死锁是如何产生的？

begin train

begin
insert into A values(XX,XX,..)

update A set SS = SS where id = SS
end

commit train

begin train

begin

update A set SS = SS where id = SS

update A set XX = XX where id = XX

end

commit train

是否有 insert update 的触发器呢。