From 65ec0046e26a284b220cc40eee080205e4a73bdc Mon Sep 17 00:00:00 2001
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Date: Thu, 7 Sep 2023 22:08:00 +0800
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 ...34\344\270\232\347\254\224\350\256\260.md" | 79 +++++++++++++++++++
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diff --git "a/25\351\231\210\344\275\263\347\202\234/9.7\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232\347\254\224\350\256\260.md" "b/25\351\231\210\344\275\263\347\202\234/9.7\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232\347\254\224\350\256\260.md"
new file mode 100644
index 0000000..deb5f5b
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+++ "b/25\351\231\210\344\275\263\347\202\234/9.7\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232\347\254\224\350\256\260.md"
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+# 笔记
+
+数据库的范式
+
+1.第一范式:要求字段的内容，不可分割，为的是保证数据的原子性。
+
+2.第二范式：要求满足第一范式的基础上，要求非主键字段要完全依赖主键（非主键要依赖整个联合主键），而不能只依赖部分。
+
+3.第三范式:满足第二范式的前提上，要求非主键属性要直接依赖于主键。
+
+# 练习
+
+CREATE DATABASE task charset utf8;
+use task;
+-- 学校
+CREATE TABLE college(
+c_id int PRIMARY KEY auto_increment,
+c_name VARCHAR(20),
+c_tel char(11),
+c_address VARCHAR(20) 
+);
+-- 专业
+CREATE TABLE major(
+m_id int PRIMARY KEY auto_increment,
+m_name VARCHAR(20),
+c_id int,
+FOREIGN KEY(c_id) REFERENCES college(c_id)
+);
+-- 班级
+CREATE TABLE clazz(
+cz_id int PRIMARY KEY auto_increment,
+cz_name VARCHAR(20),
+cz_grade VARCHAR(20),
+m_id int,
+FOREIGN KEY(m_id) REFERENCES major(m_id)
+);
+
+-- 教室
+CREATE TABLE classroom(
+cr_id int PRIMARY KEY auto_increment,
+cr_name VARCHAR(20)
+);
+-- 教师
+CREATE TABLE teacher(
+t_id int PRIMARY KEY auto_increment,
+t_name VARCHAR(20),
+c_id int,
+FOREIGN KEY(c_id) REFERENCES college(c_id)
+);
+-- 课程信息表
+CREATE TABLE message(
+ms_id int PRIMARY KEY auto_increment,
+ms_time VARCHAR(20)
+);
+-- 课程表
+CREATE TABLE timetable(
+tt_id int PRIMARY KEY auto_increment,
+tt_name VARCHAR(20),
+tt_credit int,
+c_id int,
+cr_id int,
+t_id int,
+ms_id int,
+FOREIGN KEY(c_id) REFERENCES college(c_id),
+FOREIGN KEY(cr_id) REFERENCES classroom(cr_id),
+FOREIGN KEY(t_id) REFERENCES teacher(t_id),
+FOREIGN KEY(ms_id) REFERENCES message(ms_id)
+);
+-- 学生
+CREATE TABLE student(
+s_id int PRIMARY KEY auto_increment,
+s_name VARCHAR(20),
+s_tel char(11),
+s_grade VARCHAR(20),
+cz_id int,
+tt_id int,
+FOREIGN KEY(cz_id) REFERENCES clazz(cz_id),
+FOREIGN KEY(tt_id) REFERENCES timetable(tt_id)
+);
\ No newline at end of file
-- 
Gitee