diff --git "a/57 \345\210\230\346\263\260\346\261\237/20230904\347\254\254\344\270\200\350\257\276.md" "b/57 \345\210\230\346\263\260\346\261\237/20230904\347\254\254\344\270\200\350\257\276.md"
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+作为一个程序员来说我才知道有些东西可以“走捷径”
+
+妈妈再不用担心我找不到学习资料啦
+
+如果有的学习资料需要付费可以去  **盘搜搜** 看一下有没有别人下载保存到网盘的资料
+
+视频VIP也可以跳过直接观看
+
+
+
+作为一名21世纪的青年要多社交，提升自己的表达能力
+
+了解当今社会的需求，市场需要什么就去学习什么，不当旧社会落伍
+
+上课多做笔记
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diff --git "a/57 \345\210\230\346\263\260\346\261\237/20230905ER\345\257\274\345\233\276.md" "b/57 \345\210\230\346\263\260\346\261\237/20230905ER\345\257\274\345\233\276.md"
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+今天学习了ER思维导图
+
+**1对1**
+
+将一个表里的主键放在另一个表里当外键
+
+**1对多**（n）
+
+将1的主键放在多的表里面当外键使用
+
+**多（n）对    多（n）**
+
+将两个表里的主键或关联的属性提出来做一张新的表
+
+
+
+
+
+```sql
+CREATE DATABASE university CHARSET utf8;
+SHOW DATABASES;
+USE university;
+
+
+##学院
+CREATE TABLE college(
+	collegeid int NOT NULL PRIMARY KEY,              
+	collegename VARCHAR(8) NOT NULL                   
+	);
+INSERT INTO college 
+VALUES(1,'软件工程学院');
+
+
+
+##专业
+CREATE TABLE profession(
+	professionid VARCHAR(25) NOT NULL PRIMARY KEY,    	  professionname VARCHAR(10) NOT NULL,                 collegeid int NOT NULL,                               foreign key (collegeid) references college (collegeid)
+	);
+INSERT INTO profession 
+VALUES("R001",'后端开发',1),
+			("R002",'新媒体技术',1),
+			("R003",'前端开发',1);
+
+
+
+##班级
+CREATE TABLE class(
+	classid int NOT NULL PRIMARY KEY,                         
+	classname VARCHAR(10) NOT NULL,                            
+	professionid VARCHAR(25) NOT NULL,                         
+	FOREIGN KEY (professionid) REFERENCES profession (professionid)
+	);
+
+INSERT INTO class 
+VALUES(1,'软件一班',"R001"),
+			(2,'软件二班',"R001"),
+			(3,'软件三班',"R001"),
+			(4,'软件四班',"R002"),
+			(5,'软件五班',"R002"),
+			(6,'软件六班',"R002"),
+			(7,'软件七班',"R003"),
+			(8,'软件八班',"R003"),
+			(9,'软件九班',"R003");
+
+
+
+##学生
+CREATE TABLE student(
+	studentid int NOT NULL PRIMARY KEY,                       
+	studentname VARCHAR(8) NOT NULL,                          
+	studentsex  CHAR(1) NOT NULL,                             
+	studentage  int NOT NULL,                                 
+	classid int NOT NULL,                                     
+	FOREIGN KEY (classid) REFERENCES class (classid)
+	);
+INSERT INTO student 
+VALUES(20040106,'江江','男',8,01),
+			(20040520,'娇娇','女',18,01),
+			(20040602,'锵锵','男',20,01),
+			(20040129,'刚刚','男',19,02),
+			(20040322,'铛铛','女',21,02);
+
+
+
+
+
+##科目
+CREATE TABLE subject(
+	subjectid int NOT NULL PRIMARY KEY,                         
+	subjectname VARCHAR(25)  NOT NULL                           
+	);
+
+INSERT INTO subject 
+VALUES(1111,'MYSQL'),
+			(2222,'HTML'),
+			(3333,'JAVA'),
+			(4444,'CSGO');
+
+
+
+##老师
+CREATE TABLE teacher(
+	teacherid int NOT NULL PRIMARY KEY,                      
+	teachername VARCHAR(6) NOT NULL,                        
+	subjectid int NOT NULL,                                  
+	FOREIGN KEY (subjectid) REFERENCES subject (subjectid)
+	);
+INSERT INTO teacher 
+VALUES(101,'丘丘人',1111),
+			(102,'马画藤',2222),
+			(103,'马芸',3333),
+			(104,'雷菌',4444);
+
+##课程表
+CREATE TABLE timetable( 
+	subjectid int NOT NULL PRIMARY KEY,               
+	subjectname VARCHAR(25) NOT NULL,                 
+	studytime VARCHAR(255) NOT NULL,                 
+	studyaddress VARCHAR(255) NOT NULL,               
+	teacherid int NOT NULL                           
+	);
+INSERT INTO timetable 
+VALUES(1111,'JAVA','20:30','实训8',101),
+			(2222,'HTML','24:00','实训8',102),
+			(3333,'MYSQL','12:00','实训8',103),
+			(4444,'CSGO','6:00','实训8',104);
+
+
+
+
+##选课表
+CREATE TABLE CourseSelect(   
+	subjectid int NOT NULL PRIMARY KEY,
+	subjectname VARCHAR(255) NOT NULL,               
+	teacherid int NOT NULL                           
+	);
+INSERT INTO CourseSelect 
+VALUES(4444,'CSGO',104),
+			(2222,'HTML',102),
+			(3333,'MYSQL',103),
+			(1111,'JAVA',101);
+
+
+
+##成绩表
+CREATE TABLE gradeTable(     
+	studentid int NOT NULL PRIMARY KEY,              
+	studentname VARCHAR(10) NOT NULL,                 
+	Java DOUBLE NOT NULL,                             
+	HTML DOUBLE NOT NULL,                             
+	Python DOUBLE NOT NULL,                           
+	CSS    DOUBLE NOT NULL,                          
+	FOREIGN KEY (studentid) REFERENCES student (studentid)
+	);
+INSERT INTO gradeTable 
+VALUES(20040106,'江江',100,100,100,100),
+			(20040520,'娇娇',99,99,99,99),
+			(20040602,'锵锵',65,81,19,95),
+			(20040129,'刚刚',59,59,59,59),
+			(20040322,'铛铛',100,66,88,59);
+```
+