diff --git "a/01 \345\274\240\350\276\211/.keep" "b/01 \345\274\240\350\276\211/.keep"
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git "a/01 \345\274\240\350\276\211/20230905 \347\254\254\344\270\200\345\240\202\350\257\276\345\277\203\345\276\227.md" "b/01 \345\274\240\350\276\211/20230905 \347\254\254\344\270\200\345\240\202\350\257\276\345\277\203\345\276\227.md"
new file mode 100644
index 0000000000000000000000000000000000000000..fd36f365cae6f107991c82d4fe8f2785ced6e0cd
--- /dev/null
+++ "b/01 \345\274\240\350\276\211/20230905 \347\254\254\344\270\200\345\240\202\350\257\276\345\277\203\345\276\227.md"	
@@ -0,0 +1 @@
+脚踏实地，认真完成每一个目标，别再拖沓，保持自信
\ No newline at end of file
diff --git "a/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/20230906 SQL\350\257\255\345\217\245.sql" "b/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/20230906 SQL\350\257\255\345\217\245.sql"
new file mode 100644
index 0000000000000000000000000000000000000000..88448d88002df6a6605b9de17e35da38c491aa3e
--- /dev/null
+++ "b/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/20230906 SQL\350\257\255\345\217\245.sql"	
@@ -0,0 +1,257 @@
+# 心得
+
+```text
+
+```
+
+# 代码
+
+```mysql
+SET NAMES utf8mb4;
+SET FOREIGN_KEY_CHECKS = 0;
+
+-- Table structure for class
+
+DROP TABLE IF EXISTS `class`;
+CREATE TABLE `class`  (
+  `cid` int(11) NOT NULL AUTO_INCREMENT,
+  `cName` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  `sid` int(11) NULL DEFAULT NULL,
+  `cr_id` int(11) NULL DEFAULT NULL,
+  PRIMARY KEY (`cid`) USING BTREE,
+  INDEX `sid`(`sid`) USING BTREE,
+  INDEX `cr_id`(`cr_id`) USING BTREE,
+  CONSTRAINT `class_ibfk_1` FOREIGN KEY (`sid`) REFERENCES `major` (`sid`) ON DELETE RESTRICT ON UPDATE RESTRICT,
+  CONSTRAINT `class_ibfk_2` FOREIGN KEY (`cr_id`) REFERENCES `classroom` (`cr_id`) ON DELETE RESTRICT ON UPDATE RESTRICT
+) ENGINE = InnoDB AUTO_INCREMENT = 7 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- Records of class
+
+-- ----------------------------
+
+INSERT INTO `class` VALUES (1, '一班', 1, 1);
+INSERT INTO `class` VALUES (2, '二班', 1, 2);
+INSERT INTO `class` VALUES (3, '三班', 2, 3);
+INSERT INTO `class` VALUES (4, '四班', 2, 4);
+INSERT INTO `class` VALUES (5, '五班', 3, 1);
+INSERT INTO `class` VALUES (6, '六班', 3, 2);
+
+-- ----------------------------
+
+-- Table structure for classroom
+
+-- ----------------------------
+
+DROP TABLE IF EXISTS `classroom`;
+CREATE TABLE `classroom`  (
+  `cr_id` int(11) NOT NULL AUTO_INCREMENT,
+  `address` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  PRIMARY KEY (`cr_id`) USING BTREE
+) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- ----------------------------
+
+-- Records of classroom
+
+-- ----------------------------
+
+INSERT INTO `classroom` VALUES (1, '教室101');
+INSERT INTO `classroom` VALUES (2, '教室102');
+INSERT INTO `classroom` VALUES (3, '教室103');
+INSERT INTO `classroom` VALUES (4, '教室104');
+
+-- ----------------------------
+
+-- Table structure for course
+
+-- ----------------------------
+
+DROP TABLE IF EXISTS `course`;
+CREATE TABLE `course`  (
+  `cou_id` int(11) NOT NULL AUTO_INCREMENT,
+  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  PRIMARY KEY (`cou_id`) USING BTREE
+) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- ----------------------------
+
+-- Records of course
+
+-- ----------------------------
+
+INSERT INTO `course` VALUES (1, '语文');
+INSERT INTO `course` VALUES (2, '数学');
+INSERT INTO `course` VALUES (3, '英语');
+INSERT INTO `course` VALUES (4, '计算机');
+
+-- ----------------------------
+
+-- Table structure for coursetable
+
+-- ----------------------------
+
+DROP TABLE IF EXISTS `coursetable`;
+CREATE TABLE `coursetable`  (
+  `ct_id` int(11) NOT NULL AUTO_INCREMENT,
+  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  `cr_id` int(11) NULL DEFAULT NULL,
+  PRIMARY KEY (`ct_id`) USING BTREE,
+  INDEX `cr_id`(`cr_id`) USING BTREE,
+  CONSTRAINT `coursetable_ibfk_1` FOREIGN KEY (`cr_id`) REFERENCES `classroom` (`cr_id`) ON DELETE RESTRICT ON UPDATE RESTRICT
+) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- ----------------------------
+
+-- Records of coursetable
+
+-- ----------------------------
+
+INSERT INTO `coursetable` VALUES (1, '语文', 1);
+INSERT INTO `coursetable` VALUES (2, '数学', 2);
+INSERT INTO `coursetable` VALUES (3, '英语', 3);
+INSERT INTO `coursetable` VALUES (4, '计算机', 4);
+
+-- ----------------------------
+
+-- Table structure for department
+
+-- ----------------------------
+
+DROP TABLE IF EXISTS `department`;
+CREATE TABLE `department`  (
+  `did` int(11) NOT NULL AUTO_INCREMENT,
+  `dName` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  PRIMARY KEY (`did`) USING BTREE
+) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- ----------------------------
+
+-- Records of department
+
+-- ----------------------------
+
+INSERT INTO `department` VALUES (1, '软件工程学院');
+
+-- ----------------------------
+
+-- Table structure for major
+
+-- ----------------------------
+
+DROP TABLE IF EXISTS `major`;
+CREATE TABLE `major`  (
+  `sid` int(11) NOT NULL AUTO_INCREMENT,
+  `sName` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  `did` int(11) NOT NULL,
+  PRIMARY KEY (`sid`) USING BTREE,
+  INDEX `did`(`did`) USING BTREE,
+  CONSTRAINT `major_ibfk_1` FOREIGN KEY (`did`) REFERENCES `department` (`did`) ON DELETE RESTRICT ON UPDATE RESTRICT
+) ENGINE = InnoDB AUTO_INCREMENT = 4 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- ----------------------------
+
+-- Records of major
+
+-- ----------------------------
+
+INSERT INTO `major` VALUES (1, '前端', 1);
+INSERT INTO `major` VALUES (2, '后端', 1);
+INSERT INTO `major` VALUES (3, '新媒体', 1);
+
+-- ----------------------------
+
+-- Table structure for selectcourse
+
+-- ----------------------------
+
+DROP TABLE IF EXISTS `selectcourse`;
+CREATE TABLE `selectcourse`  (
+  `se_id` int(11) NOT NULL AUTO_INCREMENT,
+  `stu_id` int(11) NULL DEFAULT NULL,
+  `cou_id` int(11) NULL DEFAULT NULL,
+  PRIMARY KEY (`se_id`) USING BTREE,
+  INDEX `stu_id`(`stu_id`) USING BTREE,
+  INDEX `cou_id`(`cou_id`) USING BTREE,
+  CONSTRAINT `selectcourse_ibfk_1` FOREIGN KEY (`stu_id`) REFERENCES `student` (`stu_id`) ON DELETE RESTRICT ON UPDATE RESTRICT,
+  CONSTRAINT `selectcourse_ibfk_2` FOREIGN KEY (`cou_id`) REFERENCES `course` (`cou_id`) ON DELETE RESTRICT ON UPDATE RESTRICT
+) ENGINE = InnoDB AUTO_INCREMENT = 7 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- ----------------------------
+
+-- Records of selectcourse
+
+-- ----------------------------
+
+INSERT INTO `selectcourse` VALUES (1, 1, 1);
+INSERT INTO `selectcourse` VALUES (2, 2, 2);
+INSERT INTO `selectcourse` VALUES (3, 3, 3);
+INSERT INTO `selectcourse` VALUES (4, 4, 4);
+INSERT INTO `selectcourse` VALUES (5, 5, 1);
+INSERT INTO `selectcourse` VALUES (6, 6, 2);
+
+-- ----------------------------
+
+-- Table structure for student
+
+-- ----------------------------
+
+DROP TABLE IF EXISTS `student`;
+CREATE TABLE `student`  (
+  `stu_id` int(11) NOT NULL AUTO_INCREMENT,
+  `id` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  `cid` int(11) NULL DEFAULT NULL,
+  PRIMARY KEY (`stu_id`) USING BTREE,
+  INDEX `cid`(`cid`) USING BTREE,
+  CONSTRAINT `student_ibfk_1` FOREIGN KEY (`cid`) REFERENCES `class` (`cid`) ON DELETE RESTRICT ON UPDATE RESTRICT
+) ENGINE = InnoDB AUTO_INCREMENT = 7 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- ----------------------------
+
+-- Records of student
+
+-- ----------------------------
+
+INSERT INTO `student` VALUES (1, '1', '梦泪', 1);
+INSERT INTO `student` VALUES (2, '2', '蜗壳', 2);
+INSERT INTO `student` VALUES (3, '3', '杰鸽', 3);
+INSERT INTO `student` VALUES (4, '4', '王毛毛', 4);
+INSERT INTO `student` VALUES (5, '5', '郑绿灰', 5);
+INSERT INTO `student` VALUES (6, '6', '郑蓝黑', 6);
+
+-- ----------------------------
+
+-- Table structure for teacher
+
+-- ----------------------------
+
+DROP TABLE IF EXISTS `teacher`;
+CREATE TABLE `teacher`  (
+  `tid` int(11) NOT NULL AUTO_INCREMENT,
+  `name` varchar(11) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
+  `cou_id` int(11) NULL DEFAULT NULL,
+  PRIMARY KEY (`tid`) USING BTREE,
+  INDEX `cou_id`(`cou_id`) USING BTREE,
+  CONSTRAINT `teacher_ibfk_1` FOREIGN KEY (`cou_id`) REFERENCES `course` (`cou_id`) ON DELETE RESTRICT ON UPDATE RESTRICT
+) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;
+
+-- ----------------------------
+
+-- Records of teacher
+
+-- ----------------------------
+
+INSERT INTO `teacher` VALUES (1, '郑弘辉', 1);
+INSERT INTO `teacher` VALUES (2, '陈姐', 2);
+INSERT INTO `teacher` VALUES (3, '张飞', 3);
+INSERT INTO `teacher` VALUES (4, '林吮吸', 4);
+
+SET FOREIGN_KEY_CHECKS = 1;
+```
+
+# 查询
+
+```MySQL
+select student.`name` as '学生姓名',class.cName AS '班级' from student,class where student.cid=class.cid and student.`name`='梦泪';
+```
+
diff --git "a/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273_ER\345\233\276.md" "b/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273_ER\345\233\276.md"
new file mode 100644
index 0000000000000000000000000000000000000000..0662e72f0f113eb7e544b5003e15bb7dad339a5f
--- /dev/null
+++ "b/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273_ER\345\233\276.md"	
@@ -0,0 +1,11 @@
+数据库设计——表之间的关系
+
+1. 一对一：将其中任一表中的主键，放到另一个表当外键（一放一，任意）
+
+2. 一对多：将一所有的表的主键，放到多的表当外键（一放多）
+
+3. 多对多：必须新建第三张表，将前面两个表的主键放进来当外键
+
+   
+
+ER图：实体关系图
\ No newline at end of file
diff --git "a/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/ER\345\233\276.png" "b/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/ER\345\233\276.png"
new file mode 100644
index 0000000000000000000000000000000000000000..b7b79d0b1b49c8ceadce6db725ac43d8b6ce9855
Binary files /dev/null and "b/01 \345\274\240\350\276\211/20230906 \350\241\250\344\271\213\351\227\264\347\232\204\345\205\263\347\263\273ER\345\233\276/ER\345\233\276.png" differ
diff --git "a/01 \345\274\240\350\276\211/20230907 \350\214\203\345\274\217.md" "b/01 \345\274\240\350\276\211/20230907 \350\214\203\345\274\217.md"
new file mode 100644
index 0000000000000000000000000000000000000000..70c6c4bd3cbe620840a60c3e4377005f1cc772e1
--- /dev/null
+++ "b/01 \345\274\240\350\276\211/20230907 \350\214\203\345\274\217.md"	
@@ -0,0 +1,7 @@
+# 笔记
+
+数据库设计的三大范式（项目小偷懒用反范式）
+
+1. 第一范式：每个属性，也就是字段要求**不可再分割**，也就要求有原子性
+2. 第二范式：在满足第一范式的基础上，要求非主键字段要完全依赖主键（有联合主键时，非主键要同时完全依赖这两个主键，而不能部分依赖）
+3. 第三范式：在满足第二范式的基础上，要求非主键字段要直接依赖于主键（建多个表）
\ No newline at end of file