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How to understand the one-to-many relationship of mysql

2025-03-02 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Internet Technology >

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This article introduces the relevant knowledge of "how to understand the one-to-many relationship of mysql". Many people will encounter such a dilemma in the operation of actual cases, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

1. One-to-many relationship means that one row of data of the master table can correspond to multiple rows of data of the slave table at the same time, and in turn, the multi-row data of the slave table points to the same row of data of the master table.

2. The application scenarios are classification table and commodity table, class table and student table, user table and order table, etc.

Example

-- create classification table CREATE TABLE category (cid INT PRIMARY KEY AUTO_INCREMENT,cname VARCHAR (50));-- create merchandise table CREATE TABLE product (pid INT PRIMARY KEY AUTO_INCREMENT,pname VARCHAR (50), price DOUBLE,cid INT)-- add a foreign key alter table product add foreign key (cid) references category (cid) to the merchandise table, "how to understand mysql one-to-many relationship". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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