数据库设计的3范式理解

原創 phpnewbie 2020-02-24 23:50

数据库设计的范式

1。去除列上的一对多关系满足第一范式

比如学生选课


学生名 课目名    该表不符合第一范式因为一个学生对应了多个课目名


2。分离与主键没有关系的字段到另外的表 满足第二范式

比如下表

学生名 教室号 教室号和学生名没有关系，因该分离该字段形成一个教室表


3。不是主键的字段不能有一对一的关系


 课目号  课目名 教师名 教师号


教师名和教师号有一对一关系，因该分离教师名和教师号

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