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所属分类：linux技术
mysql基础
mysql安装
第一种方式：使用yum进行安装
第二种方式：yum安装mariadb
yum install -y mariadb*
配置mysql的yum源: [root@lnh ~]# wget http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm --2022-07-25 17:03:13-- http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm Resolving dev.mysql.com (dev.mysql.com)... 184.29.181.90, 2600:1402:b800:1194::2e31, 2600:1402:b800:118f::2e31 Connecting to dev.mysql.com (dev.mysql.com)|184.29.181.90|:80... connected. HTTP request sent, awaiting response... 301 Moved Permanently Location: https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm [following] --2022-07-25 17:03:13-- https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm Connecting to dev.mysql.com (dev.mysql.com)|184.29.181.90|:443... connected. HTTP request sent, awaiting response... 302 Moved Temporarily Location: https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm [following] --2022-07-25 17:03:14-- https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm Resolving repo.mysql.com (repo.mysql.com)... 184.30.152.230 Connecting to repo.mysql.com (repo.mysql.com)|184.30.152.230|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 25680 (25K) [application/x-redhat-package-manager] Saving to: ‘mysql57-community-release-el7-11.noarch.rpm’ mysql57-community- 100%[================>] 25.08K 125KB/s in 0.2s 2022-07-25 17:03:15 (125 KB/s) - ‘mysql57-community-release-el7-11.noarch.rpm’ saved [25680/25680] [root@lnh ~]# rpm -Uvh mysql57-community-release-el7-11.noarch.rpm warning: mysql57-community-release-el7-11.noarch.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY Verifying... ################################# [100%] Preparing... ################################# [100%] Updating / installing... 1:mysql57-community-release-el7-11 ################################# [100%] [root@lnh ~]# rpm -Uvh mysql57-community-release-el7-11.noarch.rpm warning: mysql57-community-release-el7-11.noarch.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY Verifying... ################################# [100%] Preparing... ################################# [100%] Updating / installing... 1:mysql57-community-release-el7-11 ################################# [100%] [root@lnh ~]# dnf module disable mysql //禁用mysql MySQL Connectors Community 47 kB/s | 49 kB 00:01 MySQL Tools Community 257 kB/s | 651 kB 00:02 MySQL 5.7 Community Server 817 kB/s | 2.6 MB 00:03 Dependencies resolved. ============================================================================ Package Architecture Version Repository Size ============================================================================ Disabling modules: mysql Transaction Summary ============================================================================ Is this ok [y/N]: y Complete! [root@lnh ~]# dnf -y install mysql-community-server mysql-community-client mysql-community-common mysql-community-devel --nogpgcheck //不验证合法性进行下载 [root@lnh ~]# systemctl enable --now mysqld //设置开机自启 [root@lnh ~]# systemctl status mysqld.service //查看状态 ● mysqld.service - MySQL Server Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor > Active: active (running) since Mon 2022-07-25 17:36:19 CST; 12s ago Docs: man:mysqld(8) http://dev.mysql.com/doc/refman/en/using-systemd.html Process: 67864 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run> Process: 67814 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, sta> Main PID: 67866 (mysqld) Tasks: 27 (limit: 12221) Memory: 310.2M CGroup: /system.slice/mysqld.service └─67866 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/> Jul 25 17:36:17 lnh systemd[1]: Starting MySQL Server... Jul 25 17:36:19 lnh systemd[1]: Started MySQL Server. [root@lnh ~]# ss -antl //查看3306端口是否出现 State Recv-Q Send-Q Local Address:Port Peer Address:Port Process LISTEN 0 128 0.0.0.0:22 0.0.0.0:* LISTEN 0 128 *:80 *:* LISTEN 0 128 [::]:22 [::]:* LISTEN 0 80 *:3306 *:* [root@lnh ~]# grep "password" /var/log/mysqld.log 2022-07-25T09:36:17.891633Z 1 [Note] A temporary password is generated for root@localhost: eNGwhYkrz3_( //在日志文件中找出临时密码 [root@lnh ~]# mysql -uroot -p //使用临时密码登录 Enter password: Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 5 Server version: 5.7.38 Copyright (c) 2000, 2022, 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. //修改mysql登录密码 mysql> set global validate_password_policy=0; Query OK, 0 rows affected (0.00 sec) mysql> set global validate_password_length=1; Query OK, 0 rows affected (0.00 sec) mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'xbz123'; Query OK, 0 rows affected (0.00 sec) mysql> quit Bye [root@lnh ~]# mysql -uroot -pxbz123 //验证密码修改成功 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 6 Server version: 5.7.38 MySQL Community Server (GPL) Copyright (c) 2000, 2022, 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> [root@lnh ~]# rpm -qa |grep mysql mysql-community-client-5.7.38-1.el7.x86_64 mysql57-community-release-el7-11.noarch mysql-community-common-5.7.38-1.el7.x86_64 mysql-community-server-5.7.38-1.el7.x86_64 mysql-community-devel-5.7.38-1.el7.x86_64 mysql-community-libs-5.7.38-1.el7.x86_64 [root@lnh ~]# rpm -e mysql57-community-release-el7-11.noarch //卸载这个包防止其更新 虚拟格式化
[root@lnh ~]# mysql_secure_installation Securing the MySQL server deployment. Enter password for user root: //之前的密码 The 'validate_password' plugin is installed on the server. The subsequent steps will run with the existing configuration of the plugin. Using existing password for root. Estimated strength of the password: 50 Change the password for root ? ((Press y|Y for Yes, any other key for No) : y New password: //新密码 Re-enter new password: //再次输入 Estimated strength of the password: 50 Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y By default, a MySQL installation has an anonymous user, allowing anyone to log into MySQL without having to have a user account created for them. This is intended only for testing, and to make the installation go a bit smoother. You should remove them before moving into a production environment. Remove anonymous users? (Press y|Y for Yes, any other key for No) : y Success. Normally, root should only be allowed to connect from 'localhost'. This ensures that someone cannot guess at the root password from the network. Disallow root login remotely? (Press y|Y for Yes, any other key for No) : n //不让ssh远程连接数据库 ... skipping. By default, MySQL comes with a database named 'test' that anyone can access. This is also intended only for testing, and should be removed before moving into a production environment. Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y - Dropping test database... Success. - Removing privileges on test database... Success. Reloading the privilege tables will ensure that all changes made so far will take effect immediately. Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y Success. All done! mysql工具使用
[root@lnh ~]# mysql -V mysql Ver 14.14 Distrib 5.7.38, for Linux (x86_64) using EditLine wrapper //查看当前版本 [root@lnh ~]# mysql -uroot -pxbz123 -h127.0.0.1 //-h 指定服务器主机，默认为localhost，推荐使用ip地址 //直接在命令行输入密码登录 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 10 Server version: 5.7.38 MySQL Community Server (GPL) Copyright (c) 2000, 2022, 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> quit Bye [root@lnh ~]# mysql -uroot -p -h127.0.0.1 Enter password: Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 11 Server version: 5.7.38 MySQL Community Server (GPL) Copyright (c) 2000, 2022, 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> //注意，不推荐直接在命令行里直接用-pPASSWORD的方式登录，而是使用-p选项，然后交互式输入密码 [root@lnh ~]# mysql -uroot -p -h127.0.0.1 -e 'SHOW DATABASES;' Enter password: +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ //不登录mysql查看有哪些数据库 数据库操作
mysql> create database tushanbu; Query OK, 1 row affected (0.00 sec) //创建数据库 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | | tushanbu | +--------------------+ 5 rows in set (0.00 sec) //查看数据库 mysql> drop database tushanbu -> ; Query OK, 0 rows affected (0.01 sec) //删除数据库 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) //查看数据库 表操作
mysql> create database tushanbu; Query OK, 1 row affected (0.00 sec) //创建数据库 mysql> use tushanbu; //进入数据库 Database changed mysql> create table tsb(id int not null,name varchar(100) not null,age int); Query OK, 0 rows affected (0.02 sec) //创建表 mysql> desc tsb; //查看结构 +-------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+--------------+------+-----+---------+-------+ | id | int(11) | NO | | NULL | | | name | varchar(100) | NO | | NULL | | | age | int(11) | YES | | NULL | | +-------+--------------+------+-----+---------+-------+ 3 rows in set (0.01 sec) mysql> show tables; +--------------------+ | Tables_in_tushanbu | +--------------------+ | tsb | +--------------------+ 1 row in set (0.00 sec) //查看表 mysql> drop table tsb; Query OK, 0 rows affected (0.01 sec) //删除表 mysql> show tables; Empty set (0.00 sec) //查看 用户操作
mysql> create user 'lnh'@'127.0.0.1' identified by 'xbz123'; Query OK, 0 rows affected (0.01 sec) //创建数据库用户lnh mysql> quit Bye [root@lnh ~]# mysql -ulnh -pxbz123 -h127.0.0.1 //使用新创建的用户和密码登录 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 15 Server version: 5.7.38 MySQL Community Server (GPL) Copyright (c) 2000, 2022, 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> [root@lnh ~]# mysql -uroot -p Enter password: Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 16 Server version: 5.7.38 MySQL Community Server (GPL) Copyright (c) 2000, 2022, 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> drop user 'lnh'@'127.0.0.1'; //删除数据库用户 Query OK, 0 rows affected (0.00 sec) mysql> quit Bye [root@lnh ~]# mysql -ulnh -pxbz123 -h127.0.0.1 mysql: [Warning] Using a password on the command line interface can be insecure. ERROR 1045 (28000): Access denied for user 'lnh'@'localhost' (using password: YES //已经删除 查看命令SHOW
[root@lnh ~]# mysql -uroot -p Enter password: Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 18 Server version: 5.7.38 MySQL Community Server (GPL) Copyright (c) 2000, 2022, 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> 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 | ... 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) mysql> show databases; //查看数据库的信息 +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | | tushanbu | +--------------------+ 5 rows in set (0.00 sec) mysql> show tables from tushanbu; //不进去其数据库查看表 +--------------------+ | Tables_in_tushanbu | +--------------------+ | tsb | +--------------------+ 1 row in set (0.00 sec) mysql> desc tushanbu.tsb; //不进入数据库查看数据库表的结构 +-------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+--------------+------+-----+---------+-------+ | id | int(11) | NO | | NULL | | | name | varchar(100) | NO | | NULL | | | age | int(11) | YES | | NULL | | +-------+--------------+------+-----+---------+-------+ 3 rows in set (0.00 sec) mysql> show create table tushanbu.tsb; //创建某表的创建命令 +-------+---------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +-------+---------------------------------------------------------------------------------------------------------------------------------------------------+ | tsb | CREATE TABLE `tsb` ( `id` int(11) NOT NULL, `name` varchar(100) NOT NULL, `age` int(11) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1 | +-------+---------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> use tushanbu; mysql> show table status like 'tsb'G *************************** 1. row *************************** Name: tsb Engine: InnoDB Version: 10 Row_format: Dynamic Rows: 0 Avg_row_length: 0 Data_length: 16384 Max_data_length: 0 Index_length: 0 Data_free: 0 Auto_increment: NULL Create_time: 2022-07-25 22:12:10 Update_time: NULL Check_time: NULL Collation: latin1_swedish_ci Checksum: NULL Create_options: Comment: 1 row in set (0.00 sec) //进入数据库查看表的状态 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] [AS] query_expression CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name { LIKE old_tbl_name | (LIKE old_tbl_name) } create_definition: { col_name column_definition | {INDEX | KEY} [index_name] [index_type] (key_part,...) [index_option] ... | {FULLTEXT | SPATIAL} [INDEX | KEY] [index_name] (key_part,...) [index_option] ... | [CONSTRAINT [symbol]] PRIMARY KEY [index_type] (key_part,...) //获取创建表的帮助 MySQL 数据类型
MySQL中定义数据字段的类型对数据库的优化是非常重要的。MySQL支持多种类型，大致可以分为三类：数值、日期/时间和字符串(字符)类型。 数值类型 MySQL支持所有标准SQL数值数据类型。这些类型包括严格数值数据类型(INTEGER、SMALLINT、DECIMAL和NUMERIC)，以及近似数值数据类型(FLOAT、REAL和DOUBLE PRECISION)。 关键字INT是INTEGER的同义词，关键字DEC是DECIMAL的同义词。BIT数据类型保存位字段值，并且支持MyISAM、MEMORY、InnoDB和BDB表。作为SQL标准的扩展，MySQL也支持整数类型TINYINT、MEDIUMINT和BIGINT。下面的表显示了需要的每个整数类型的存储和范围 
注意：char(n) 和 varchar(n) 中括号中 n 代表字符的个数，并不代表字节个数，比如 CHAR(30) 就可以存储 30 个字符。 CHAR 和 VARCHAR 类型类似，但它们保存和检索的方式不同。它们的最大长度和是否尾部空格被保留等方面也不同。在存储或检索过程中不进行大小写转换。 BINARY 和 VARBINARY 类似于 CHAR 和 VARCHAR，不同的是它们包含二进制字符串而不要非二进制字符串。也就是说，它们包含字节字符串而不是字符字符串。这说明它们没有字符集，并且排序和比较基于列值字节的数值值。 BLOB 是一个二进制大对象，可以容纳可变数量的数据。有 4 种 BLOB 类型：TINYBLOB、BLOB、MEDIUMBLOB 和 LONGBLOB。它们区别在于可容纳存储范围不同。 有 4 种 TEXT 类型：TINYTEXT、TEXT、MEDIUMTEXT 和 LONGTEXT。对应的这 4 种 BLOB 类型，可存储的最大长度不同，可根据实际情况选择。 
