Table of Contents
1 搭建环境
1.2 编辑器 PhpStorm 2019.3
- keymap: emacs
- Terminal: M + F12
1.3 连接数据库
- 使用 PhpStorm Terminal 连接登录（其他终端也可以），默认安装不需要密码
- 为了方便使用，添加环境变量（mysql.exe 所在路径）
C:wamp64www>mysql -h127.0.0.1 -uroot -p Enter password: Welcome to the MariaDB monitor. Commands end with ; or g. Your MariaDB connection id is 46 Server version: 10.4.10-MariaDB mariadb.org binary distribution Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. MariaDB [(none)]>
- 格式：mysql -h[IP] -u用户名 -p[密码]
- 退出：exit
2 数据库操作
2.1 注释
MariaDB [db1]> -- 单行注释（-- 之后有空格） MariaDB [db1]> /* /*> 这里是多行注释 /*> 这里是多行注释 /*> 这里是多行注释 /*> */ MariaDB [db1]>
2.2 显示字符集
MariaDB [(none)]> show charset; +----------+-----------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +----------+-----------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | dec8 | DEC West European | dec8_swedish_ci | 1 | | cp850 | DOS West European | cp850_general_ci | 1 | | hp8 | HP West European | hp8_english_ci | 1 | ...... | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | | armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 | | utf8 | UTF-8 Unicode | utf8_general_ci | 3 | ...... | utf32 | UTF-32 Unicode | utf32_general_ci | 4 | | binary | Binary pseudo charset | binary | 1 | | geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 | +----------+-----------------------------+---------------------+--------+
2.3 指定使用的字符集
推荐是用 utf8（常用的还有 gbk）
MariaDB [(none)]> set names utf8;
2.4 显示校验规则（排序规则）
MariaDB [(none)]> show collation; +------------------------------+----------+------+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +------------------------------+----------+------+---------+----------+---------+ | big5_chinese_ci | big5 | 1 | Yes | Yes | 1 | | big5_bin | big5 | 84 | | Yes | 1 | ...... | armscii8_nopad_bin | armscii8 | 1088 | | Yes | 1 | | utf8_general_ci | utf8 | 33 | Yes | Yes | 1 | | utf8_bin | utf8 | 83 | | Yes | 1 | | utf8_unicode_ci | utf8 | 192 | | Yes | 8 | ...... | eucjpms_japanese_nopad_ci | eucjpms | 1121 | | Yes | 1 | | eucjpms_nopad_bin | eucjpms | 1122 | | Yes | 1 | +------------------------------+----------+------+---------+----------+---------+
2.5 查看数据库引擎
MariaDB [(none)]> show engines; +--------------------+---------+-------------------------------------------------------------------------------------------------+--------------+------+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +--------------------+---------+-------------------------------------------------------------------------------------------------+--------------+------+------------+ | CSV | YES | Stores tables as CSV files | NO | NO | NO | | MRG_MyISAM | YES | Collection of identical MyISAM tables | NO | NO | NO | | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO | | Aria | YES | Crash-safe tables with MyISAM heritage. Used for internal temporary tables and privilege tables | NO | NO | NO | | MyISAM | DEFAULT | Non-transactional engine with good performance and small data footprint | NO | NO | NO | | SEQUENCE | YES | Generated tables filled with sequential values | YES | NO | YES | | InnoDB | YES | Supports transactions, row-level locking, foreign keys and encryption for tables | YES | YES | YES | | PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO | +--------------------+---------+-------------------------------------------------------------------------------------------------+--------------+------+------------+
2.6 显示数据库
MariaDB [(none)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | test | +--------------------+
2.7 创建数据库
-- 一般格式 -- create database 'db_name' [charset 'charset_name'] [collate 'collate_name']; -- db_name：数据库名称 -- charset_name: 字符串名称，一般用utf8（show charset） -- collate_name一般都使用默认值（show collation） MariaDB [(none)]> create database db1 charset utf8; MariaDB [(none)]> show databases ; +--------------------+ | Database | +--------------------+ | db1 | | information_schema | | mysql | | performance_schema | | test | +--------------------+ MariaDB [(none)]> create database db2; MariaDB [(none)]> show databases ; +--------------------+ | Database | +--------------------+ | db1 | | db2 | | information_schema | | mysql | | performance_schema | | test | +--------------------+
2.8 显示数据库创建语句
MariaDB [(none)]> show create database db1; +----------+--------------------------------------------------------------+ | Database | Create Database | +----------+--------------------------------------------------------------+ | db1 | CREATE DATABASE `db1` /*!40100 DEFAULT CHARACTER SET utf8 */ | +----------+--------------------------------------------------------------+ MariaDB [(none)]> show create database db2; +----------+----------------------------------------------------------------+ | Database | Create Database | +----------+----------------------------------------------------------------+ | db2 | CREATE DATABASE `db2` /*!40100 DEFAULT CHARACTER SET latin1 */ | +----------+----------------------------------------------------------------+
2.9 修改数据库
MariaDB [(none)]> alter database db2 charset gbk; MariaDB [(none)]> show create database db2; +----------+-------------------------------------------------------------+ | Database | Create Database | +----------+-------------------------------------------------------------+ | db2 | CREATE DATABASE `db2` /*!40100 DEFAULT CHARACTER SET gbk */ | +----------+-------------------------------------------------------------+
2.10 删除数据库
MariaDB [(none)]> drop database db2; MariaDB [(none)]> show databases ; +--------------------+ | Database | +--------------------+ | db1 | | information_schema | | mysql | | performance_schema | | test | +--------------------+
2.11 指定使用某个数据库
MariaDB [(none)]> use db1;
Database changed
MariaDB [db1]>
3 表操作
3.1 显示表
MariaDB [db1]> show tables;
Empty set (0.001 sec)
3.2 创建表
-- create table 'table_name' ('field'[,...]) [charset='charset_name'] [engine='engine_name']; -- table_name: 表名称 -- field: 字段（比较复杂单独整理） -- charset_name: 字符集名称（show charset） -- engine_name: 存储引擎（show engines） MariaDB [db1]> create table tb1 (id int) charset = utf8 engine = InnoDB; MariaDB [db1]> create table tb2 (id int); MariaDB [db1]> show tables; +---------------+ | Tables_in_db1 | +---------------+ | tb1 | | tb2 | +---------------+
3.2.1 字段
create table 'table_name' ('field'[,…]) charset = utf8 engine = InnoDB; table_name: 表名称 field：字段名称 数据类型 ['字段属性', …]
- 数据类型
- 整数
类型 tinyint smallint midumint int bigint 字节大小 1 2 3 4 8 MariaDB [db1]> create table t (t tinyint, s smallint unsigned, m mediumint unsigned, i int, b bigint); MariaDB [db1]> select * from t; +------+------+------+------+------+ | t | s | m | i | b | +------+------+------+------+------+ | 1 | 2 | 3 | 4 | 5 | +------+------+------+------+------+ -- tityint 超过一个字节 MariaDB [db1]> insert into t values (512, 2, 3, 4, 5); ERROR 1264 (22003): Out of range value for column 't' at row 1 -- 声明是无符号数确使用有符号数 MariaDB [db1]> insert into t values (1, -2, 3, 4, 5); ERROR 1264 (22003): Out of range value for column 's' at row 1
- 小数
类型 单精度浮点数 双精度浮点数 定点小数 字节大小 4 8 有效位 7（内定） 17（内定） 65（max，人为指定，是精确小数） MariaDB [db1]> drop table t; MariaDB [db1]> create table t (f float unsigned, d double, e decimal(16, 3)); MariaDB [db1]> insert into t values (1.1212121, 1.1111212121, 123.12311); MariaDB [db1]> insert into t values (1100000011, 222222222, 200.16655111); MariaDB [db1]> select * from t; +---------+--------------+---------+ | f | d | e | +---------+--------------+---------+ | 1.12121 | 1.1111212121 | 123.123 | | 111.667 | 222222222 | 200.167 | +---------+--------------+---------+ -- 小数精度不足就会四舍五入 -- float 中有效位不足，精度缺失 -- decimal 中小数只保留指定的位数
- 日期时间
类型 year date time datetime timestamp 格式 0000 0000-00-00 00:00:00 0000-00-00 00:00:00 特性 自动获取，修改数据时自动更新 场景 创建 修改 起始时间是：1970-0-0 0:0:0，设定的时间不能再这个之前
MariaDB [db1]> drop table t; MariaDB [db1]> create table t (y year, d date, t time, dt datetime, s timestamp); MariaDB [db1]> insert into t values ('2000', '1990-1-1', '12:12:12', '1999-9-9 9:9:9', null); MariaDB [db1]> select * from t; +------+------------+----------+---------------------+---------------------+ | y | d | t | dt | s | +------+------------+----------+---------------------+---------------------+ | 2000 | 1990-01-01 | 12:12:12 | 1999-09-09 09:09:09 | 2019-12-29 21:36:58 | +------+------------+----------+---------------------+---------------------+ -- 使用now()函数 MariaDB [db1]> insert into t (dt) values (now()); MariaDB [db1]> select * from t; +------+------------+----------+---------------------+---------------------+ | y | d | t | dt | s | +------+------------+----------+---------------------+---------------------+ | 2000 | 1990-01-01 | 12:12:12 | 1999-09-09 09:09:09 | 2019-12-29 21:36:58 | | NULL | NULL | NULL | 2019-12-29 21:39:17 | 2019-12-29 21:39:17 | +------+------------+----------+---------------------+---------------------+ -- 修改了第二条数据 -- datetime 类型不变，timestamp 自动更新了 MariaDB [db1]> update t set y = '2008' where d is null; MariaDB [db1]> select * from t; +------+------------+----------+---------------------+---------------------+ | y | d | t | dt | s | +------+------------+----------+---------------------+---------------------+ | 2000 | 1990-01-01 | 12:12:12 | 1999-09-09 09:09:09 | 2019-12-29 21:36:58 | | 2008 | NULL | NULL | 2019-12-29 21:39:17 | 2019-12-29 21:40:46 | +------+------------+----------+---------------------+---------------------+
- 字符串
类型 char varchar text mediumtext longtext 长度 固定长度（速度最快） 实际长度小于设定长度则为实际长度 不能设置长度 同 text 同 text 大小 255 65532 65535 1600万左右 40亿左右 是否保存在行中 是 是 否 否 否 - char/varchar 中长度指的是字符个数（但是总字节数不能超）
- 每个汉字占用字节数：gbk->2 utf8->3
- 表中每行最大字节数为65535
MariaDB [db1]> drop table t; MariaDB [db1]> create table t (c char(8), v varchar(8), t text, mt mediumtext, lt longtext); MariaDB [db1]> insert into t (c, v, t, mt, lt) values ('大家好，欢迎大家', '你们也好', '文章','内容','太大了'); MariaDB [db1]> select * from t; +------------------+----------+------+------+--------+ | c | v | t | mt | lt | +------------------+----------+------+------+--------+ | 大家好，欢迎大家 | 你们也好 | 文章 | 内容 | 太大了 | +------------------+----------+------+------+--------+
- 多选/单选
字符串中的空白字符也是有效字符，使用多个组合应该加空格
名称 enum set 作用 单选 多选 数字索引规律 1 2 3 4 5 … 1 2 4 8 16 … 最大项 65535 64 set 可以使用组合索引，有 2^64 种组合
MariaDB [db1]> create table t3 ( -> birth_year enum('1990', '2000', '2010', '2020'), -> sports set('basketball', 'football', 'baseball', 'badminton', 'volleyball') -> ) charset=utf8 engine = InnoDB; MariaDB [db1]> desc t3; +------------+------------------------------------------------------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------+------------------------------------------------------------------+------+-----+---------+-------+ | birth_year | enum('1990','2000','2010','2020') | YES | | NULL | | | sports | set('basketball','football','baseball','badminton','volleyball') | YES | | NULL | | +------------+------------------------------------------------------------------+------+-----+---------+-------+ MariaDB [db1]> insert into t3 values ('1990', 'football,badminton'); Query OK, 1 row affected (0.008 sec) -- 添加一条数据 MariaDB [db1]> select * from t3; +------------+--------------------+ | birth_year | sports | +------------+--------------------+ | 1990 | football,badminton | +------------+--------------------+ -- 使用数字代替字符串 -- enum 1 2 3 4 5 ... -- set 1 2 4 8 ... （可以组合使用） MariaDB [db1]> insert into t3 values (2, 5); MariaDB [db1]> select * from t3; +------------+---------------------+ | birth_year | sports | +------------+---------------------+ | 1990 | football,badminton | | 2000 | basketball,baseball | +------------+---------------------+ -- 使用的数字超出定义值报错 MariaDB [db1]> insert into t3 values (2, 32); ERROR 1265 (01000): Data truncated for column 'sports' at row 1
- 整数
- 字段属性
property primary key auto_increment unique key default null comment 含义 主键 自增长 唯一键 默认值 是否为空 说明性内容 值 not null / null 使用特性 一般用在 ID 上 默认每次加1，一般用在 ID 上 作为约束条件 一般放在最后 表字段中最大使用次数 1 1 多次 是否可以为空 否 是 数据是否可以重复 否 否 使用所有的属性
MariaDB [db1]> drop table t; MariaDB [db1]> create table t ( -> id int primary key auto_increment, -> name char(32) not null unique key, -> age tinyint unsigned not null comment '人的年纪', -> fav enum('ball', 'swimming') not null default 'ball' comment '爱好' -> ); MariaDB [db1]> insert into t (name, age) values ('alex', 110); MariaDB [db1]> select * from t; +----+------+-----+------+ | id | name | age | fav | +----+------+-----+------+ | 1 | alex | 110 | ball | +----+------+-----+------+ MariaDB [db1]> desc t; +-------+-------------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | char(32) | NO | UNI | NULL | | | age | tinyint(3) unsigned | NO | | NULL | | | fav | enum('ball','swimming') | NO | | ball | | +-------+-------------------------+------+-----+---------+----------------+
主键的其他声明方式
-- 额外声明主键 MariaDB [db1]> create table t1 ( -> id int auto_increment, -> name char(32), -> primary key(id) -> ); MariaDB [db1]> desc t1; +-------+----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+----------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | char(32) | YES | | NULL | | +-------+----------+------+-----+---------+----------------+ -- 使用联合主键 MariaDB [db1]> drop table t1; MariaDB [db1]> create table t1 ( -> title char(32), -> author char(32), -> primary key(title, author) -> ); MariaDB [db1]> desc t1; +--------+----------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+----------+------+-----+---------+-------+ | title | char(32) | NO | PRI | NULL | | | author | char(32) | NO | PRI | NULL | | +--------+----------+------+-----+---------+-------+
3.3 显示表结构
MariaDB [db1]> desc tb2; +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | +-------+---------+------+-----+---------+-------+ -- Field: 字段名称 -- Type: 字段类型（比较复杂单独整理） -- Null: 是否为空 -- Key: 索引（键） -- Default: 默认值 -- Extra: 附加
| 项 | Field | Type | Null | Key | Default | Extra |
|---|---|---|---|---|---|---|
| 含义 | 名称 | 数据类型 | 是否可以为空 | 索引（键） | 默认值 | 附加 |
3.4 显示创建表的语句
MariaDB [db1]> show create table tb1; +-------+---------------------------------------------------------------------------------------+ | Table | Create Table | +-------+---------------------------------------------------------------------------------------+ | tb1 | CREATE TABLE `tb1` (`id` int(11) DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=utf8 | +-------+---------------------------------------------------------------------------------------+ MariaDB [db1]> show create table tb2; +-------+---------------------------------------------------------------------------------------+ | Table | Create Table | +-------+---------------------------------------------------------------------------------------+ | tb2 | CREATE TABLE `tb2` (`id` int(11) DEFAULT NULL) ENGINE=MyISAM DEFAULT CHARSET=utf8 | +-------+---------------------------------------------------------------------------------------+ -- 默认字符集和数据库使用的一样 -- 默认的存储引擎是 MyISAM
3.5 重命名表
MariaDB [db1]> alter table tb2 rename rubbish; MariaDB [db1]> show tables; +---------------+ | Tables_in_db1 | +---------------+ | rubbish | | tb1 | +---------------+
3.6 删除表
MariaDB [db1]> drop table rubbish; MariaDB [db1]> show tables; +---------------+ | Tables_in_db1 | +---------------+ | tb1 | +---------------+
3.7 修改字段
3.7.1 增加
MariaDB [db1]> alter table tb1 add ext varchar(32); MariaDB [db1]> desc tb1; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | ext | varchar(32) | YES | | NULL | | +-------+-------------+------+-----+---------+-------+ -- 在前面添加 MariaDB [db1]> alter table tb1 add name char(8) first; MariaDB [db1]> desc tb1; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | name | char(8) | YES | | NULL | | | id | int(11) | YES | | NULL | | | ext | varchar(32) | YES | | NULL | | +-------+-------------+------+-----+---------+-------+ -- 在指定字段后面添加 MariaDB [db1]> alter table tb1 add age int after id; MariaDB [db1]> desc tb1; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | name | char(8) | YES | | NULL | | | id | int(11) | YES | | NULL | | | age | int(11) | YES | | NULL | | | ext | varchar(32) | YES | | NULL | | +-------+-------------+------+-----+---------+-------+
3.7.2 修改属性
MariaDB [db1]> desc tb1; +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | name | char(8) | YES | | NULL | | | id | int(11) | YES | | NULL | | | age | int(11) | YES | | NULL | | | ext | text | YES | | NULL | | +-------+---------+------+-----+---------+-------+ -- 和创建时一样指定字段的属性 MariaDB [db1]> alter table tb1 modify id int primary key auto_increment; MariaDB [db1]> desc tb1; +-------+---------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+----------------+ | name | char(8) | YES | | NULL | | | id | int(11) | NO | PRI | NULL | auto_increment | | age | int(11) | YES | | NULL | | | ext | text | YES | | NULL | | +-------+---------+------+-----+---------+----------------+
3.7.3 替换
MariaDB [db1]> alter table tb1 change ext ext_name char(128); MariaDB [db1]> desc tb1; +----------+-----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+-----------+------+-----+---------+----------------+ | name | char(8) | YES | | NULL | | | id | int(11) | NO | PRI | NULL | auto_increment | | age | int(11) | YES | | NULL | | | ext_name | char(128) | YES | | NULL | | +----------+-----------+------+-----+---------+----------------+
3.7.4 删除
MariaDB [db1]> alter table tb1 drop name; MariaDB [db1]> alter table tb1 drop ext_name; MariaDB [db1]> desc tb1; +-------+---------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | age | int(11) | YES | | NULL | | +-------+---------+------+-----+---------+----------------+
4 数据操作
这里都是一些简单的基本操作
4.1 查询
-- 查找是重点和难点单独整理 MariaDB [db1]> select * from tb1;
4.2 添加
MariaDB [db1]> desc tb1; +-------+---------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | age | int(11) | YES | | NULL | | +-------+---------+------+-----+---------+----------------+ -- 插入数据 MariaDB [db1]> insert into tb1 (age) values (100); MariaDB [db1]> select * from tb1; +----+------+ | id | age | +----+------+ | 1 | 100 | +----+------+ -- 简写方式插入数据 MariaDB [db1]> insert into tb1 values (null, 11); MariaDB [db1]> select * from tb1; +----+------+ | id | age | +----+------+ | 1 | 100 | | 2 | 11 | +----+------+
4.3 修改
MariaDB [db1]> update tb1 set age = 55 where id = 1; MariaDB [db1]> select * from tb1; +----+------+ | id | age | +----+------+ | 1 | 55 | | 2 | 11 | +----+------+
4.4 删除
MariaDB [db1]> delete from tb1 where id = 2; MariaDB [db1]> select * from tb1; +----+------+ | id | age | +----+------+ | 1 | 55 | +----+------+
5 数据库选型例子
- 年龄：tinyint，整型足够大
- 薪水；double | decimal 精度要保证
- 中国人口: int 整型足够大
- 文章发表日期：datetime 记录日期
- 文章修改日期：timestamp 记录修改时间
Created: 2019-12-30 周一 10:07