bitsCN.com
mysql整型数据宽度,字段的零填充和符号 1.整型的符号在mysql中数字数据类型是有符号和无符号两种,当然整型也是,在定义一个字段的时候可以这么使用 age tinyint unsigned,unsigned代表是无符号,即都是大与等于0 的数 如果这样使用是默认有符号的age tinyint , 2.整型的数据宽度和零填充 如下语句 age tinyint(1) , 代表age这个字段是1个字符宽度, 但是如果不设置零填充式无效的,mysql将会忽略那个字符宽度。 如下语句是有有效的 age tinyint(1) zerofill,只有在设置了零填充之后数据宽度才会有效,如果插入的数据时20将会插入出错。 注意:zerofill的字段默认是无符号的,就是大于等于零的数据,输入小与零的数字将会报错。这个语句和上个语句是同一个意思:age tinyint(1) unsigned zerofill.还有一点注意的地方,最好为字段设置上默认值,要不然不容易比较在mysql中字段值是null时,和谁都能不能比较,甚至和null自己本身都不能比较,比较结果都是null。 作者 com360 bitsCN.com

This article explores optimizing MySQL memory usage in Docker. It discusses monitoring techniques (Docker stats, Performance Schema, external tools) and configuration strategies. These include Docker memory limits, swapping, and cgroups, alongside

This article addresses MySQL's "unable to open shared library" error. The issue stems from MySQL's inability to locate necessary shared libraries (.so/.dll files). Solutions involve verifying library installation via the system's package m

The article discusses using MySQL's ALTER TABLE statement to modify tables, including adding/dropping columns, renaming tables/columns, and changing column data types.

This article compares installing MySQL on Linux directly versus using Podman containers, with/without phpMyAdmin. It details installation steps for each method, emphasizing Podman's advantages in isolation, portability, and reproducibility, but also

This article provides a comprehensive overview of SQLite, a self-contained, serverless relational database. It details SQLite's advantages (simplicity, portability, ease of use) and disadvantages (concurrency limitations, scalability challenges). C

This guide demonstrates installing and managing multiple MySQL versions on macOS using Homebrew. It emphasizes using Homebrew to isolate installations, preventing conflicts. The article details installation, starting/stopping services, and best pra

Article discusses configuring SSL/TLS encryption for MySQL, including certificate generation and verification. Main issue is using self-signed certificates' security implications.[Character count: 159]

Article discusses popular MySQL GUI tools like MySQL Workbench and phpMyAdmin, comparing their features and suitability for beginners and advanced users.[159 characters]


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Dreamweaver CS6
Visual web development tools

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
