如何使用 MySQL 在带有外键的表中插入值?

2021-11-20 00:00:00 insert foreign-keys mysql

我有这两个表只是例如:

I have these two tables just for example:

TAB_TEACHER
- id_teacher   // primary key, autoincrement
- name_teacher // a varchar

TAB_STUDENT
- id_student    // primary key, autoincrement
- name_student  // a varchar
- id_teacher_fk // foreign key reference to a teacher (TAB_TEACHER)

我想知道这两种情况下怎么插入:

I want to know how to insert in these two cases:

案例 1 - 插入一个新的学生和一个预先存在的老师，所以我必须得到带有老师姓名的外键

CASE 1 - INSERT a new Student with an pre-existing TEACHER, so I have to get the foreign key with a teacher name

案例 2 - 插入一个新学生和一个新老师(我在创建学生的同时创建的老师)

CASE 2 - INSERT a new Student with a new TEACHER (the teacher I'm creating in the same time I'm creating the student)

推荐答案

http://dev.mysql.com/doc/refman/5.0/en/insert-select.html

对于案例 1:

INSERT INTO TAB_STUDENT(name_student, id_teacher_fk)
SELECT 'Joe The Student', id_teacher
  FROM TAB_TEACHER
 WHERE name_teacher = 'Professor Jack'
 LIMIT 1

对于 case2，你只需要做 2 个单独的插入语句

For case2 you just have to do 2 separate insert statements

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