From 77a26156c87506d2ec4701baa347287b7d201bd4 Mon Sep 17 00:00:00 2001
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Date: Thu, 7 Sep 2023 20:35:14 +0800
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diff --git "a/09 \346\233\271\346\255\243\346\263\242/20230907  \346\225\260\346\215\256\345\272\223\351\253\230\347\272\247.md" "b/09 \346\233\271\346\255\243\346\263\242/20230907  \346\225\260\346\215\256\345\272\223\351\253\230\347\272\247.md"
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+++ "b/09 \346\233\271\346\255\243\346\263\242/20230907  \346\225\260\346\215\256\345\272\223\351\253\230\347\272\247.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
+
+```mysql
+create database tnfb charset utf8;
+use tnfb;
+
+#院系表
+create table college(
+	cll_id int primary key auto_increment,
+	cll_name varchar(10), 
+	cll_tel char(11)
+);
+
+#专业表
+create table major(
+	m_id int primary key auto_increment,
+	m_name varchar(10), 
+	cll_id int,
+	foreign key(cll_id) references college(cll_id)
+);
+
+#班级表
+create table clazz(
+	c_id int primary key auto_increment,
+	c_name varchar(10), 
+  c_grabe int,
+	m_id int,
+	foreign key(m_id) references major(m_id)
+);
+
+#教室表
+create table classroom(
+	cl_id int primary key auto_increment,
+	cl_name varchar(10)
+);
+#教师表
+create table teacher(
+	t_id int primary key auto_increment,
+	t_name varchar(10),
+	cll_id int,
+	foreign key(cll_id) REFERENCES college(cll_id)
+);
+#课程信息表
+create table message(
+	me_id int primary key auto_increment,
+	me_time varchar(20)
+);
+#课程表 （教室号，上课时间，上课时间段，教师号，课程号，院系号）
+create table course(
+	co_id int primary key auto_increment,
+	co_name varchar(10),
+	co_credit int,
+  cll_id int,
+	cl_id int,
+	me_id int,
+	t_id int,
+	foreign key(cl_id) REFERENCES classroom(cl_id),
+	foreign key(cll_id) REFERENCES college(cll_id),
+	foreign key(me_id) REFERENCES message(me_id),
+	foreign key(t_id) REFERENCES teacher(t_id)
+);
+
+#学生表
+create table student(
+	st_id int primary key auto_increment,
+	st_name varchar(10), 
+  st_grabe int,
+	c_id int,
+	co_id int,
+	foreign key(co_id) references course(co_id),
+	foreign key(c_id) references clazz(c_id)
+);
+
+
+
+
+```
+
-- 
Gitee