哪个表应该是父表，哪个应该是子表？ [英] Which table should be Parent table and which should be child table?

问题描述

嗨有两个表Auther和书。
我很困惑我应该保留哪个表作为父表，哪个表应该是用于制作外键约束的子表。

  CREATE TABLE author 
（
 author_id NUMBER（3）CONSTRAINT athr_aid_pk PRIMARY KEY，
 author_name VARCHAR2（30）
）; 
 
 CREATE TABLE books 
（
 book_id NUMBER（3），
 book_title VARCHAR2（30），
 book_price NUMBER（3），
 
）; 
  

请告诉我哪个表应该是父表，为什么？

原因： >这是一个多对多关系。

解决方案：创建一个单独的表，包含两个列author_id，book_id都是外键。

Hi have two tables Auther and Books. I am confused that to which table should i keep as parent table and which should be child table for making foreign key constraint.

CREATE TABLE author
 (
    author_id NUMBER(3) CONSTRAINT athr_aid_pk PRIMARY KEY,
    author_name VARCHAR2(30)
 );

 CREATE TABLE books
 (
    book_id NUMBER(3),
    book_title VARCHAR2(30),
    book_price NUMBER(3),

 );

Please explain me which table should be Parent table and why?

解决方案

Answer: None.

Reason: This is a many-to-many relationship. An author can have any number of books written, also a book can have more than one author.

Solution: Make a separate table with two columns author_id, book_id both are foreign keys.

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