文章目錄
- Day3
- 約束
- 非空約束
- 唯一性約束（unique）
- 主鍵約束
- 主鍵作用？
- 主鍵分類？
- mysql主鍵值自增 auto_increment(重要)
- 外鍵約束
- 存儲引擎
- 事務
- 索引
- 查看sql執行計劃
- 視圖
- DBA命令
- 數據庫設計三範式（重點）
- 一對一設計方案？
- 其餘兩天鏈接
- 看到最後的幫忙點個==贊==👍🙏 謝謝！
Day3
約束
什麼是約束？
常見約束？
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-hti6ZS8M-1589887307541)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518122426190.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222424389.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
非空約束
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-2z8ie5Y1-1589887307555)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518123251890.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222440238.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-VdITP4Ok-1589887307560)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518175905928.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222453802.png#pic_center)
唯一性約束（unique）
但可以爲null
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-TNKSIBWP-1589887307565)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518174611950.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222513605.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
表集約束 多個列添加unique
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-Rsg4WBqu-1589887307571)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518175255243.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222532594.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
列級約束
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-kAm48S5O-1589887307581)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518175528303.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222547143.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
主鍵約束
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-7EeKNzW2-1589887307583)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518180241556.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222645278.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-WwkmT863-1589887307586)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518185513343.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222700216.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-yy63mRfM-1589887307589)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200518185615115.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222718737.png#pic_center)
主鍵作用？
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-fkD3oiw4-1589887307593)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519102806860.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222734985.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-ovQG5OPQ-1589887307599)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519102912278.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222751809.png#pic_center)
主鍵分類？
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-7Q0kDoJ7-1589887307603)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519103435237.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222809517.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-oOjGkTxt-1589887307611)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519103657857.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222824189.png#pic_center)
mysql主鍵值自增 auto_increment(重要)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-wcwzEJpV-1589887307633)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519103834684.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222839200.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
外鍵約束
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-XZ13oOXa-1589887307639)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519104729316.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222853216.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-UtxBon27-1589887307642)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519105110537.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222905738.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
刪表順序
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-dP2YyoBD-1589887307652)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519105432327.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222918936.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-0HTTC0gU-1589887307656)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519111041466.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222933376.png#pic_center)
存儲引擎
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-TAiNBYqs-1589887307658)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519112400247.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519222946743.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
什麼是存儲引擎？
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-01dGVf4y-1589887307660)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519112424739.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223001741.png#pic_center)
查看當前mysql支持的存儲引擎
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-CPBzUY5w-1589887307668)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519112505676.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223014138.png#pic_center)
常見存儲引擎
MyISAM
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-44wvfuAU-1589887307672)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519112637720.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223030905.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
innoDB
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-tDvXBEJa-1589887307680)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519113231718.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223043697.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
MEMORY
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-U140E1aX-1589887307692)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519113618133.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/2020051922310218.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
事務
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-3IrVl3t0-1589887307695)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519115214427.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223120885.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
DML語句
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-bTysI8Af-1589887307698)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519115327449.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223137136.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-fbLzknLm-1589887307702)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519115556448.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223149695.png#pic_center)
事物的特性
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-hUqql9tj-1589887307705)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519122559526.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223205418.png#pic_center)
關於事務之間的隔離性（4個級別）
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-9v62vCwM-1589887307708)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519123633256.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223219651.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
事務流程
start transaction
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-fFeN12kU-1589887307714)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519124600275.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223233233.png#pic_center)
演示兩個事務
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-vo0mXb1h-1589887307718)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519130155106.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223247584.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
索引
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-v0YWB2fT-1589887307722)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519130311431.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223302384.png#pic_center)
索引爲什麼提高了效率？
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-BrlodfR4-1589887307729)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519130433801.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223314455.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-gebJl0ce-1589887307733)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519130705954.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223334384.png#pic_center)
什麼時候給字段添加索引？
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-VVRrMUC4-1589887307742)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519131027755.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223346773.png#pic_center)
主鍵和unique自動添加索引
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-8Uhe3oND-1589887307748)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519131110288.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223402475.png#pic_center)
創建刪除索引
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-fGYWCJcc-1589887307766)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519131432565.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223417155.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-xNdGSRp9-1589887307771)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519131604935.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223429279.png#pic_center)
索引的實現原理
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-XRdh4EQV-1589887307777)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519132907825.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223441642.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-oqtSuMdx-1589887307782)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519133013954.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223457176.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjQ5MjIz,size_16,color_FFFFFF,t_70#pic_center)
索引分類？
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-Atuz91uq-1589887307785)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519133127460.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223515173.png#pic_center)
索引失效 like
模糊查詢第一個是%
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-MX1dQPv3-1589887307793)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519133216507.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223530431.png#pic_center)
查看sql執行計劃
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-pVSDQLlr-1589887307796)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519131509983.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/2020051922354275.png#pic_center)
視圖
創建刪除
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-H0Qc94l0-1589887307802)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519172826025.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223554748.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-nbSOXUkZ-1589887307805)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519172939593.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223608387.png#pic_center)
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-abHMN0Zr-1589887307810)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519173006200.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223623321.png#pic_center)
視圖作用
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-Vvl54tT8-1589887307816)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519173924511.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223636932.png#pic_center)
DBA命令
導出數據
指定庫
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-AWxamVC3-1589887307819)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519174621446.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223653571.png#pic_center)
指定表
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-w22NCZQG-1589887307832)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519174631661.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223714649.png#pic_center)
導入數據
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-lyn5NVju-1589887307842)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519174501677.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223735619.png#pic_center)
數據庫設計三範式（重點）
![[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-gFV1RJYQ-1589887307844)(%E6%95%B0%E6%8D%AE%E5%BA%93%20MySQL.assets/image-20200519175452263.png)]](https://pic1.xuehuaimg.com/proxy/csdn/https://img-blog.csdnimg.cn/20200519223751459.png#pic_center)
三範式有哪些？
口訣：
二 多對多？三張表，關係表加外鍵
三 一對多？ 兩張表，多的表加外鍵**
（*）面試加分項
一對一設計方案？
主鍵共享
外鍵唯一
其餘兩天鏈接
第一天鏈接：https://blog.csdn.net/qq_43649223/article/details/106221325
第二天鏈接：https://blog.csdn.net/qq_43649223/article/details/106225054
看到最後的幫忙點個贊👍🙏 謝謝！![在這裏插入圖片描述]()
