diff --git "a/17 \350\221\243\345\272\206\345\274\272/\347\254\254\344\270\200\346\254\241.md" "b/17 \350\221\243\345\272\206\345\274\272/\347\254\254\344\270\200\346\254\241.md"
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+到了大二，公共课没有了，专业课变多了，说明了课程更难，更高级了，得用课余时间来消化每节课上课的知识，跟上老师的节奏，少睡觉，多学习，少打游戏
+
+
diff --git "a/17 \350\221\243\345\272\206\345\274\272/\347\254\254\344\272\214\346\254\241\345\244\232\350\241\250.md" "b/17 \350\221\243\345\272\206\345\274\272/\347\254\254\344\272\214\346\254\241\345\244\232\350\241\250.md"
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+笔记
+
+数据库画图，用Visio
+
+表和表的关系
+
+一对一是一个主建放在另外一个当主建，
+
+一对多主建放在更多的表当外键，
+
+多对多必须三个表
+
+```mysql
+CREATE DATABASE sjkgaoj CHARSET utf8;
+use sjkgaoj;
+CREATE TABLE xueyuan(
+xueyuan_id int PRIMARY KEY, #学院编号
+xueyuanmz VARCHAR(30) #学院名称
+);
+INSERT INTO xueyuan VALUES
+(1,"软件工程学院"),
+(2,"财经商贸学院"),
+(3,"智能制造学院");
+
+
+
+CREATE TABLE zhuanye(
+zhuanye_id int PRIMARY KEY, #专业编号
+zhuanyemz VARCHAR(30),    #专业名称
+xueyuan_id INT, #学院编号
+FOREIGN key(xueyuan_id) REFERENCES xueyuan(xueyuan_id)
+);
+INSERT into zhuanye VALUES
+(1,"前端",1),
+(2,"后端",1),
+(3,"新媒体",1),
+(4,"电子商务",2);
+
+CREATE TABLE banji(
+banji_id int PRIMARY KEY, #班级编号
+banjimc VARCHAR(30),#班级名称
+zhuanye_id int, #专业编号
+FOREIGN KEY(zhuanye_id) REFERENCES zhuanye(zhuanye_id)
+);
+
+INSERT INTO banji VALUES
+(1,"软件一班",1),
+(2,"软件二班",1),
+(3,"软件三班",1),
+(4,"软件四班",1),
+(5,"软件五班",2);
+
+CREATE TABLE xuesheng(
+xuesheng_id int PRIMARY key, #学生号数
+xueshengxm VARCHAR(30),#学生姓名
+banji_id INT,#班级编号
+FOREIGN key (banji_id) REFERENCES banji(banji_id)
+);
+
+INSERT INTO xuesheng VALUES
+(1,"张三",1),
+(2,"李四",1),
+(3,"王五",2),
+(4,"赵六",3);
+
+CREATE TABLE jiaoshi(
+jiaoshi_id int PRIMARY KEY,#教室编号
+jiaoshi VARCHAR(30), #教室名称
+banji_id INT, #b班级编号
+FOREIGN key (banji_id) REFERENCES banji(banji_id)
+);
+
+INSERT INTO jiaoshi VALUES
+(8,"实训8",1),
+(1,"实训1",2),
+(2,"实训2",3),
+(3,"实训3",4);
+
+CREATE TABLE laoshi(
+laoshi_id int PRIMARY key,#老师编号
+laoshimz VARCHAR(30),#老师名字
+zhuanye_id int,#专业编号
+FOREIGN KEY (zhuanye_id) REFERENCES zhuanye(zhuanye_id)
+);
+INSERT into laoshi VALUES
+(1,"邱邱",2),
+(2,"问问",1),
+(3,"嗯嗯",3); 
+```