简体中文(ZH-CN) English(EN) 繁体中文(ZH-TW) 日本語(JA) 한국어(KO) Melayu(MS) Français(FR) Deutsch(DE)
Home > Backend Development > PHP Tutorial > body text

数据库筑表时，NOT NULL有什么用？

WBOY
Release： 2016-06-13 13:27:06
Original
1602 people have browsed it

数据库建表时，NOT NULL有什么用？？？
我建了一张测试表，其中有几个NOT NULL的字段，我在插入行的时候，没给这几个字段赋值，也插入成功了。
那NOT NULL还有什么用呢？

------解决方案--------------------
mysql里NULL 和 ''不是一回事，你只设置了字段为NOT NULL ，是可以插入空串的

探讨

真的。。。表结构：
Related labels：
mysql NOT null
source：php.cn
Previous article： PHP+XML缓存怎么快速读取指定的值 Next article： <meta http-equiv="imagetoolbar" content="no" />是什么意思？该怎么处理
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Latest Issues
In React, localstorage.getItem returns null index.js：importReactfrom'react';importReactDOMfrom'react-dom/client';import'./index.css';i...
From 2024-04-05 14:18:19
0
1
1523
POST request works fine when using Postman but not when using React axios and Spring Boot backend From the react console I get the error "Unable to load resource: Server response stat...
From 2024-04-05 13:07:01
0
1
396
How to retrieve values ​​of unselected rows in HTML data table using jquery I'm trying to get the value of all rows where the button was not clicked. For example, whe...
From 2024-04-05 09:26:49
0
1
1418
Forced refresh is a consequence of accessing undefined paths or error pages in Next.js Accessing an undefined path or error page causes Next.js to do a hard refresh, causing my ...
From 2024-04-05 08:32:46
0
1
400
MySQL: Find columns matching integers in a text (CSV) column This table has a text column that stores references to other records in CSV format, for ex...
From 2024-04-04 18:03:46
0
1
291
Related Topics
More>
Popular Recommendations
Popular Tutorials
More>
Related Tutorials
Popular Recommendations
Latest courses
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn：Public welfare online PHP training，Help PHP learners grow quickly！