
并:

差:


笛卡兒積:


投影:


選擇:


交:


聯(lián)接:


除:



例題:




參考連接:
https://blog.csdn.net/qq_37521566/article/details/80854134
https://blog.csdn.net/qq_39368007/article/details/86586563
元組演算



例題:








? ?參考連接:
????????????https://blog.csdn.net/xqf309/article/details/8865269
參考連接:
https://blog.csdn.net/qq_37521566/article/details/80854134
https://blog.csdn.net/qq_39368007/article/details/86586563
? ?參考連接:
????????????https://blog.csdn.net/xqf309/article/details/8865269