数据库配置

2021/4/30 2:25:41

编程Tag： 配置 mysql Set 数据库 name CI sec 0.00

本文主要是介绍数据库配置，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

//创建数据库
//语法：CREATE DATABASE [IF NOT EXISTS] 'DB_NAME';
[root@localhost ~]# mysql -uroot -phuangfang123!
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.34 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> CREATE DATABASE IF NOT EXISTS teng;                 //创建teng数据库
Query OK, 1 row affected (0.00 sec)

mysql> SHOW DATABASES;             //查看数据库
+--------------------+
| Database           |
+--------------------+
| information_schema |
| huang              |
| mysql              |
| performance_schema |
| sys                |
| teng               |
+--------------------+
6 rows in set (0.01 sec)
mysql> DROP DATABASE IF EXISTS huang             //删除huang数据库
    -> ;
Query OK, 1 row affected (0.01 sec)

mysql> SHOW DATABASES                             //查看数据库
    -> ;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| teng               |
+--------------------+
5 rows in set (0.01 sec)

表操作

//创建表
//语法：CREATE TABLE table_name (col1 datatype 修饰符,col2 datatype 修饰符) ENGINE='存储引擎类型';
mysql> use teng;             //进入teng数据库
Database changed

mysql>  CREATE TABLE jia(id int NOT NULL,name VARCHAR(100) NOT NULL,age tinyint);   //创建jia表
Query OK, 0 rows affected (0.01 sec)

//查看当前数据库有哪些表
mysql> SHOW TABLES;
+----------------+
| Tables_in_teng |
+----------------+
| jia            |
+----------------+
1 row in set (0.00 sec)

//删除表
//语法：DROP TABLE [ IF EXISTS ] 'table_name';
mysql> DROP TABLE jia                       //删除jia表
    -> ;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW TABLES;
Empty set (0.00 sec)

用户操作
mysql用户帐号由两部分组成，如’USERNAME’@‘HOST’，表示此USERNAME只能从此HOST上远程登录

这里（‘USERNAME’@‘HOST’）的HOST用于限制此用户可通过哪些主机远程连接mysql程序，其值可为：

IP地址，如：172.16.12.129
通配符
%：匹配任意长度的任意字符，常用于设置允许从任何主机登录
_：匹配任意单个字符

//数据库用户创建
//语法：CREATE USER 'username'@'host' [IDENTIFIED BY 'password'];
mysql>  CREATE USER 'teng'@'192.168.11.135' IDENTIFIED BY 'P@ssword123!';             //创建用户teng
Query OK, 0 rows affected (0.00 sec)


//删除数据库用户
mysql> DROP USER 'teng'@'192.168.11.135';
Query OK, 0 rows affected (0.01 sec)

查看命令SHOW

mysql> show character set             //查看支持的所有字符集
    -> ;
+----------+---------------------------------+---------------------+--------+
| 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 |
| koi8r    | KOI8-R Relcom Russian           | koi8r_general_ci    |      1 |
| latin1   | cp1252 West European            | latin1_swedish_ci   |      1 |
| latin2   | ISO 8859-2 Central European     | latin2_general_ci   |      1 |
| swe7     | 7bit Swedish                    | swe7_swedish_ci     |      1 |
| ascii    | US ASCII                        | ascii_general_ci    |      1 |
| ujis     | EUC-JP Japanese                 | ujis_japanese_ci    |      3 |
| sjis     | Shift-JIS Japanese              | sjis_japanese_ci    |      2 |
| hebrew   | ISO 8859-8 Hebrew               | hebrew_general_ci   |      1 |
| tis620   | TIS620 Thai                     | tis620_thai_ci      |      1 |
| euckr    | EUC-KR Korean                   | euckr_korean_ci     |      2 |
| koi8u    | KOI8-U Ukrainian                | koi8u_general_ci    |      1 |
| gb2312   | GB2312 Simplified Chinese       | gb2312_chinese_ci   |      2 |
| greek    | ISO 8859-7 Greek                | greek_general_ci    |      1 |
| cp1250   | Windows Central European        | cp1250_general_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 |
| ucs2     | UCS-2 Unicode                   | ucs2_general_ci     |      2 |
| cp866    | DOS Russian                     | cp866_general_ci    |      1 |
| keybcs2  | DOS Kamenicky Czech-Slovak      | keybcs2_general_ci  |      1 |
| macce    | Mac Central European            | macce_general_ci    |      1 |
| macroman | Mac West European               | macroman_general_ci |      1 |
| cp852    | DOS Central European            | cp852_general_ci    |      1 |
| latin7   | ISO 8859-13 Baltic              | latin7_general_ci   |      1 |
| utf8mb4  | UTF-8 Unicode                   | utf8mb4_general_ci  |      4 |
| cp1251   | Windows Cyrillic                | cp1251_general_ci   |      1 |
| utf16    | UTF-16 Unicode                  | utf16_general_ci    |      4 |
| utf16le  | UTF-16LE Unicode                | utf16le_general_ci  |      4 |
| cp1256   | Windows Arabic                  | cp1256_general_ci   |      1 |
| cp1257   | Windows Baltic                  | cp1257_general_ci   |      1 |
| 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 |
| gb18030  | China National Standard GB18030 | gb18030_chinese_ci  |      4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.00 sec)


mysql> show engines;          //查看当前数据库支持的所有存储引擎
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                        | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys     | YES          | YES  | YES        |
| 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         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO   | NO         |
| MyISAM             | YES     | MyISAM storage engine                                          | NO           | NO   | NO         |
| CSV                | YES     | CSV storage engine                                             | NO           | NO   | NO         |
| ARCHIVE            | YES     | Archive storage engine                                         | NO           | NO   | NO         |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                             | NO           | NO   | NO         |
| FEDERATED          | NO      | Federated MySQL storage engine                                 | NULL         | NULL | NULL       |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
9 rows in set (0.00 sec)

 //查看数据库信息
mysql> show databases
    -> ;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)


 //不进入某数据库而列出其包含的所有表
 mysql> SHOW TABLES FROM huang;
+-----------------+
| Tables_in_huang |
+-----------------+
| student         |
+-----------------+
1 row in set (0.00 sec)


//查看表结构
//语法：DESC [db_name.]table_name;
mysql> desc huang.student;
+-------+--------------+------+-----+---------+----------------+
| Field | Type         | Null | Key | Default | Extra          |
+-------+--------------+------+-----+---------+----------------+
| id    | int(11)      | NO   | PRI | NULL    | auto_increment |
| name  | varchar(100) | NO   |     | NULL    |                |
| age   | tinyint(4)   | YES  |     | NULL    |                |
+-------+--------------+------+-----+---------+----------------+
3 rows in set (0.00 sec)


//查看某表的创建命令
//语法：SHOW CREATE TABLE table_name;
mysql> SHOW CREATE TABLE huang.student;
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table   | Create Table                                                                                                                                                                                                    |
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| student | CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `age` tinyint(4) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=latin1 |
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

//查看某表的状态
//语法：SHOW TABLE STATUS LIKE 'table_name'\G
mysql> use huang
Database changed
mysql> SHOW TABLE STATUS LIKE 'huang'\G
Empty set (0.00 sec)

获取帮助

mysql>  HELP CREATE TABLE;
Name: 'CREATE TABLE'
Description:
Syntax:
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    (create_definition,...)
    [table_options]
    [partition_options]

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    [(create_definition,...)]
    [table_options]
    [partition_options]
    [IGNORE | REPLACE]

DML操作
DML操作包括增(INSERT)、删(DELETE)、改(UPDATE)、查(SELECT)，均属针对表的操作。

INSERT语句

mysql> use huang
Database changed
mysql> INSERT INTO student (id,name,age) VALUE (1,'tom',20);
ERROR 1146 (42S02): Table 'huang.student' doesn't exist
mysql> create table student(id int(11) not null auto_increment primary key,name varchar(100) not null,age tinyint(4));
Query OK, 0 rows affected (0.02 sec)

mysql> desc student;
+-------+--------------+------+-----+---------+----------------+
| Field | Type         | Null | Key | Default | Extra          |
+-------+--------------+------+-----+---------+----------------+
| id    | int(11)      | NO   | PRI | NULL    | auto_increment |
| name  | varchar(100) | NO   |     | NULL    |                |
| age   | tinyint(4)   | YES  |     | NULL    |                |
+-------+--------------+------+-----+---------+----------------+
3 rows in set (0.01 sec)

SELECT语句
字段column表示法

表示符代表什么？

所有字段
as 字段别名，如col1 AS alias1
当表名很长时用别名代替
条件判断语句WHERE

操作类型常用操作符
操作符 >，<，>=，<=，=，!=
BETWEEN column# AND column#
LIKE：模糊匹配
RLIKE：基于正则表达式进行模式匹配
IS NOT NULL：非空
IS NULL：空
条件逻辑操作 AND
OR
NOT
ORDER BY：排序，默认为升序（ASC）

ORDER BY语句意义
ORDER BY ‘column_name’ 根据column_name进行升序排序
ORDER BY ‘column_name’ DESC 根据column_name进行降序排序
ORDER BY ’column_name’ LIMIT 2 根据column_name进行升序排序
并只取前2个结果
ORDER BY ‘column_name’ LIMIT 1,2 根据column_name进行升序排序
并且略过第1个结果取后面的2个结果

//DML操作之查操作select
//语法：SELECT column1,column2,... FROM table_name [WHERE clause] [ORDER BY 'column_name' [DESC]] [LIMIT [m,]n];

mysql> desc student;
+-------+--------------+------+-----+---------+----------------+
| Field | Type         | Null | Key | Default | Extra          |
+-------+--------------+------+-----+---------+----------------+
| id    | int(11)      | NO   | PRI | NULL    | auto_increment |
| name  | varchar(100) | NO   |     | NULL    |                |
| age   | tinyint(4)   | YES  |     | NULL    |                |
+-------+--------------+------+-----+---------+----------------+
3 rows in set (0.01 sec)

mysql> select * from student;
Empty set (0.00 sec)



mysql> select name from student;
+-------------+
| name        |
+-------------+
| tom         |
| jerry       |
| wangqing    |
| sean        |
| zhangshan   |
| zhangshan   |
| lisi        |
| chengshuo   |
| wangwu      |
| qiuyi       |
| qiuxiaotian |
+-------------+
11 rows in set (0.00 sec)


mysql> SELECT * FROM student ORDER BY age;
+----+-------------+------+
| id | name        | age  |
+----+-------------+------+
|  7 | lisi        | NULL |
|  9 | wangwu      |    3 |
|  8 | chengshuo   |   10 |
| 10 | qiuyi       |   15 |
|  1 | tom         |   20 |
|  6 | zhangshan   |   20 |
| 11 | qiuxiaotian |   20 |
|  2 | jerry       |   23 |
|  3 | wangqing    |   25 |
|  5 | zhangshan   |   26 |
|  4 | sean        |   28 |
+----+-------------+------+
11 rows in set (0.00 sec)

mysql> SELECT * FROM student ORDER BY age DESC;
+----+-------------+------+
| id | name        | age  |
+----+-------------+------+
|  4 | sean        |   28 |
|  5 | zhangshan   |   26 |
|  3 | wangqing    |   25 |
|  2 | jerry       |   23 |
|  1 | tom         |   20 |
|  6 | zhangshan   |   20 |
| 11 | qiuxiaotian |   20 |
| 10 | qiuyi       |   15 |
|  8 | chengshuo   |   10 |
|  9 | wangwu      |    3 |
|  7 | lisi        | NULL |
+----+-------------+------+
11 rows in set (0.00 sec)

mysql> SELECT * FROM student ORDER BY age limit 2;
+----+--------+------+
| id | name   | age  |
+----+--------+------+
|  7 | lisi   | NULL |
|  9 | wangwu |    3 |
+----+--------+------+
2 rows in set (0.00 sec)

mysql> SELECT * FROM student WHERE age >= 25;
+----+-----------+------+
| id | name      | age  |
+----+-----------+------+
|  3 | wangqing  |   25 |
|  4 | sean      |   28 |
|  5 | zhangshan |   26 |
+----+-----------+------+
3 rows in set (0.00 sec)


mysql>  SELECT * FROM student WHERE age >= 25 AND name = 'zhangshan';
+----+-----------+------+
| id | name      | age  |
+----+-----------+------+
|  5 | zhangshan |   26 |
+----+-----------+------+
1 row in set (0.00 sec)

mysql>  select * from student where age is not null;
+----+-------------+------+
| id | name        | age  |
+----+-------------+------+
|  1 | tom         |   20 |
|  2 | jerry       |   23 |
|  3 | wangqing    |   25 |
|  4 | sean        |   28 |
|  5 | zhangshan   |   26 |
|  6 | zhangshan   |   20 |
|  8 | chengshuo   |   10 |
|  9 | wangwu      |    3 |
| 10 | qiuyi       |   15 |
| 11 | qiuxiaotian |   20 |
+----+-------------+------+
10 rows in set (0.00 sec)

update语句
//DML操作之改操作update
//语法：UPDATE table_name SET column1 = new_value1[,column2 = new_value2,…] [WHERE clause] [ORDER BY ‘column_name’ [DESC]] [LIMIT [m,]n];

mysql> select * from student;
+----+-------------+------+
| id | name        | age  |
+----+-------------+------+
|  1 | tom         |   20 |
|  2 | jerry       |   23 |
|  3 | wangqing    |   25 |
|  4 | sean        |   28 |
|  5 | zhangshan   |   26 |
|  6 | zhangshan   |   20 |
|  7 | lisi        | NULL |
|  8 | chengshuo   |   10 |
|  9 | wangwu      |    3 |
| 10 | qiuyi       |   15 |
| 11 | qiuxiaotian |   20 |
+----+-------------+------+
11 rows in set (0.00 sec)
片

delete语句
//DML操作之删操作delete
//语法：DELETE FROM table_name [WHERE clause] [ORDER BY ‘column_name’ [DESC]] [LIMIT [m,]n];

mysql> select * from student;
+----+-------------+------+
| id | name        | age  |
+----+-------------+------+
|  1 | tom         |   20 |
|  2 | jerry       |   23 |
|  3 | wangqing    |   25 |
|  4 | sean        |   28 |
|  5 | zhangshan   |   26 |
|  6 | zhangshan   |   20 |
|  8 | chengshuo   |   10 |
|  9 | wangwu      |    3 |
| 10 | qiuyi       |   15 |
| 11 | qiuxiaotian |   20 |
+----+-------------+------+
10 rows in set (0.00 sec)

mysql> delete from student;
Query OK, 10 rows affected (0.00 sec)

mysql> select * from student;
Empty set (0.00 sec)

mysql> desc student;
+-------+--------------+------+-----+---------+----------------+
| Field | Type         | Null | Key | Default | Extra          |
+-------+--------------+------+-----+---------+----------------+
| id    | int(11)      | NO   | PRI | NULL    | auto_increment |
| name  | varchar(100) | NO   |     | NULL    |                |
| age   | tinyint(4)   | YES  |     | NULL    |                |
+-------+--------------+------+-----+---------+----------------+
3 rows in set (0.00 sec)

truncate语句
truncate与delete的区别：

语句类型特点
delete DELETE删除表内容时仅删除内容，但会保留表结构
DELETE语句每次删除一行，并在事务日志中为所删除的每行记录一项
可以通过回滚事务日志恢复数据
非常占用空间
truncate 删除表中所有数据，且无法恢复
表结构、约束和索引等保持不变，新添加的行计数值重置为初始值
执行速度比DELETE快，且使用的系统和事务日志资源少
通过释放存储表数据所用的数据页来删除数据，并且只在事务日志中记录页的释放
对于有外键约束引用的表，不能使用TRUNCATE TABLE删除数据
不能用于加入了索引视图的表
//语法：TRUNCATE table_name;

mysql> truncate student;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from student;
Empty set (0.00 sec)

mysql> desc student;
+-------+--------------+------+-----+---------+----------------+
| Field | Type         | Null | Key | Default | Extra          |
+-------+--------------+------+-----+---------+----------------+
| id    | int(11)      | NO   | PRI | NULL    | auto_increment |
| name  | varchar(100) | NO   |     | NULL    |                |
| age   | tinyint(4)   | YES  |     | NULL    |                |
+-------+--------------+------+-----+---------+----------------+
3 rows in set (0.00 sec)

DCL操作
创建授权grant
权限类型(priv_type)

权限类型代表什么？
ALL 所有权限
SELECT 读取内容的权限
INSERT 插入内容的权限
UPDATE 更新内容的权限
DELETE 删除内容的权限
指定要操作的对象db_name.table_name

表示方式意义
. 所有库的所有表
db_name 指定库的所有表
db_name.table_name 指定库的指定表
WITH GRANT OPTION：被授权的用户可将自己的权限副本转赠给其他用户，说白点就是将自己的权限完全复制给另一个用户。不建议使用。

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| huang              |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

//授权teng用户在数据库本机上登录访问所有数据库
mysql> GRANT ALL ON *.* TO 'teng'@'localhost' IDENTIFIED BY 'P@ssword123!';
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> GRANT ALL ON *.* TO 'teng'@'127.0.0.1' IDENTIFIED BY 'P@ssword123!';
Query OK, 0 rows affected, 1 warning (0.00 sec)


//授权teng用户在192.168.11.134上远程登录访问wangqingge数据库
mysql> GRANT ALL ON teng.* TO 'teng'@'192.168.11.134' IDENTIFIED BY 'P@ssword123!';
Query OK, 0 rows affected, 1 warning (0.00 sec)

//授权teng用户在所有位置上远程登录访问wangqingge数据库
mysql> GRANT ALL ON *.* TO 'teng'@'%' IDENTIFIED BY 'P@ssword123!';
Query OK, 0 rows affected, 1 warning (0.00 sec)

4.3.2 查看授权
//查看当前登录用户的授权信息

mysql>  SHOW GRANTS;
+---------------------------------------------------------------------+
| Grants for root@localhost                                           |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION        |
+---------------------------------------------------------------------+
2 rows in set (0.00 sec)

//查看指定用户teng的授权信息
mysql> SHOW GRANTS FOR teng;
+-----------------------------------------------+
| Grants for teng@%                         |
+-----------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'teng'@'%' |
+-----------------------------------------------+
1 row in set (0.00 sec)

mysql> SHOW GRANTS FOR 'teng'@'localhost';
+---------------------------------------------------+
| Grants for teng@localhost                         |
+---------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'teng'@'localhost' |
+---------------------------------------------------+
1 row in set (0.00 sec)

mysql> SHOW GRANTS FOR 'teng'@'127.0.0.1';
+---------------------------------------------------+
| Grants for teng@127.0.0.1                         |
+---------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'teng'@'127.0.0.1' |
+---------------------------------------------------+
1 row in set (0.00 sec)

取消授权REVOKE

mysql> REVOKE ALL ON *.* FROM 'teng'@'192.168.11.134';
Query OK, 0 rows affected (0.00 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)

注意：mysql服务进程启动时会读取mysql库中的所有授权表至内存中：

GRANT或REVOKE等执行权限操作会保存于表中，mysql的服务进程会自动重读授权表，并更新至内存中
对于不能够或不能及时重读授权表的命令，可手动让mysql的服务进程重读授权表
mysql> FLUSH PRIVILEGES;

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