从入门到删库跑路的过程

技术2022-07-10 159

数据库简介

数据库的发展史

萌芽阶段：文件系统使用磁盘文件来存储数据初级阶段：第一代数据库出现了网状模型、层次模型的数据库中级阶段：第二代数据库关系型数据库和结构化查询语言高级阶段：新一代数据库关系-对象型数据库

NoSQL非关系数据库：Not Only SQL

数据库管理系统

数据库是数据的汇集，它以一定的组织形式存于存储介质上

DBMS是管理数据库的系统软件，它实现数据库系统的各种功能。是数据库系统的核心

DBA：负责数据库的规划、设计、协调、维护和管理等工作

应用程序指以数据库为基础的应用程序

数据库管理系统的优点

相互关联的数据的集合较少的数据冗余程序与数据相互独立保证数据的安全、可靠最大限度地保证数据的正确性数据可以并发使用并能同时保证一致性

MYSQL(马云生气了)系列

官方网址：

https://www.mysql.com/ http://mariadb.org/ https://www.percona.com

官方文档:

https://dev.mysql.com/doc/ https://mariadb.com/kb/en/ https://www.percona.com/software/mysql-database/percona-server

版本演变： MySQL：5.1 --> 5.5 --> 5.6 --> 5.7 -->8.0 MariaDB：5.5 -->10.0–> 10.1 --> 10.2 --> 10.3

MYSQL的特性

插件式存储引擎：也称为“表类型”，存储管理器有多种实现版本，功能和特性可能均略有差别；用户可根据需要灵活选择,Mysql5.5.5开始innoDB引擎是MYSQL默认引擎 MyISAM ==> Aria InnoDB ==> XtraDB单进程，多线程诸多扩展和新特性提供了较多测试组件开源

安装MYSQL

Mariadb安装方式：

源代码：编译安装二进制格式的程序包：展开至特定路径，并经过简单配置后即可使用程序包管理器管理的程序包CentOS 安装光盘项目官方：https://downloads.mariadb.org/mariadb/repositories/ 国内镜像：https://mirrors.tuna.tsinghua.edu.cn/mariadb/yum/ https://mirrors.tuna.tsinghua.edu.cn/mysql/yum/

centos6是最后自带mysql的版本了，在centos7中默认的是mariadb

centos 7的mariadb的安装yum源

[mariadb] name=MariaDBbaseurl=https://mirrors.tuna.tsinghua.edu.cn/mariadb/yum/10.2/centos74-amd64/ gpgcheck=0 # 安装方法 sudo yum install MariaDB-server MariaDB-client

centos7中默认版本为5.5.64

[root@localhost ~]# yum info mariadb Loaded plugins: fastestmirror, langpacks Loading mirror speeds from cached hostfile Available Packages Name : mariadb Arch : x86_64 Epoch : 1 Version : 5.5.64 Release : 1.el7 Size : 8.7 M Repo : base Summary : A community developed branch of MySQL URL : http://mariadb.org License : GPLv2 with exceptions and LGPLv2 and BSD Description : MariaDB is a community developed branch of MySQL. : MariaDB is a multi-user, multi-threaded SQL database server. : It is a client/server implementation consisting of a server daemon (mysqld) : and many different client programs and libraries. The base package : contains the standard MariaDB/MySQL client programs and generic MySQL files.

配置yum源安装mariadb

[root@localhost ~]# vim /etc/yum.repos.d/mariadb.repo [mariadb] name = MariaDB baseurl = http://yum.mariadb.org/10.2/centos7-amd64 gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB gpgcheck=1 [root@localhost ~]# yum repolist Loaded plugins: fastestmirror, langpacks Loading mirror speeds from cached hostfile repo id repo name status !base Base 10,097 epel Epel 13,329 mariadb MariaDB 95 repolist: 23,521

文件包内容

[root@localhost ~]# rpm -ql MariaDB-server /etc/init.d/mysql /etc/logrotate.d/mysql /etc/my.cnf.d /etc/my.cnf.d/enable_encryption.preset /etc/my.cnf.d/server.cnf /etc/security/user_map.conf /lib64/security/pam_user_map.so /usr/bin/aria_chk /usr/bin/aria_dump_log /usr/bin/aria_ftdump /usr/bin/aria_pack /usr/bin/aria_read_log /usr/bin/galera_new_cluster /usr/bin/galera_recovery /usr/bin/innochecksum /usr/bin/mariadb-service-convert /usr/bin/my_print_defaults /usr/bin/myisam_ftdump /usr/bin/myisamchk /usr/bin/myisamlog /usr/bin/myisampack /usr/bin/mysql_convert_table_format /usr/bin/mysql_fix_extensions /usr/bin/mysql_install_db /usr/bin/mysql_secure_installation /usr/bin/mysql_setpermission /usr/bin/mysql_tzinfo_to_sql /usr/bin/mysql_upgrade /usr/bin/mysqld_multi /usr/bin/mysqld_safe /usr/bin/mysqld_safe_helper /usr/bin/mysqldumpslow /usr/bin/mysqlhotcopy /usr/bin/perror /usr/bin/replace /usr/bin/resolve_stack_dump /usr/bin/resolveip /usr/bin/wsrep_sst_common /usr/bin/wsrep_sst_mariabackup /usr/bin/wsrep_sst_mysqldump /usr/bin/wsrep_sst_rsync /usr/bin/wsrep_sst_rsync_wan /usr/bin/wsrep_sst_xtrabackup /usr/bin/wsrep_sst_xtrabackup-v2 /usr/lib/systemd/system/mariadb.service /usr/lib/systemd/system/mariadb@.service /usr/lib/systemd/system/mariadb@bootstrap.service.d /usr/lib/systemd/system/mariadb@bootstrap.service.d/use_galera_new_cluster.conf /usr/lib/sysusers.d /usr/lib/sysusers.d/mariadb.conf /usr/lib/tmpfiles.d/mariadb.conf /usr/lib64/libmysqld.so /usr/lib64/libmysqld.so.19 /usr/lib64/mysql /usr/lib64/mysql/plugin /usr/lib64/mysql/plugin/auth_ed25519.so /usr/lib64/mysql/plugin/auth_pam.so /usr/lib64/mysql/plugin/auth_socket.so /usr/lib64/mysql/plugin/disks.so /usr/lib64/mysql/plugin/file_key_management.so /usr/lib64/mysql/plugin/ha_archive.so /usr/lib64/mysql/plugin/ha_blackhole.so /usr/lib64/mysql/plugin/ha_federated.so /usr/lib64/mysql/plugin/ha_federatedx.so /usr/lib64/mysql/plugin/ha_mroonga.so /usr/lib64/mysql/plugin/ha_sphinx.so /usr/lib64/mysql/plugin/ha_spider.so /usr/lib64/mysql/plugin/handlersocket.so /usr/lib64/mysql/plugin/locales.so /usr/lib64/mysql/plugin/metadata_lock_info.so /usr/lib64/mysql/plugin/query_cache_info.so /usr/lib64/mysql/plugin/query_response_time.so /usr/lib64/mysql/plugin/semisync_master.so /usr/lib64/mysql/plugin/semisync_slave.so /usr/lib64/mysql/plugin/server_audit.so /usr/lib64/mysql/plugin/simple_password_check.so /usr/lib64/mysql/plugin/sql_errlog.so /usr/lib64/mysql/plugin/wsrep_info.so /usr/sbin/mysqld /usr/sbin/rcmysql /usr/share/doc/MariaDB-server-10.2.32 /usr/share/doc/MariaDB-server-10.2.32/COPYING /usr/share/doc/MariaDB-server-10.2.32/COPYING.AGPLv3 /usr/share/doc/MariaDB-server-10.2.32/COPYING.GPLv2 /usr/share/doc/MariaDB-server-10.2.32/CREDITS /usr/share/doc/MariaDB-server-10.2.32/EXCEPTIONS-CLIENT /usr/share/doc/MariaDB-server-10.2.32/INSTALL-BINARY /usr/share/doc/MariaDB-server-10.2.32/PATENTS /usr/share/doc/MariaDB-server-10.2.32/README-wsrep /usr/share/doc/MariaDB-server-10.2.32/README.md /usr/share/doc/MariaDB-server-10.2.32/THIRDPARTY /usr/share/man/man1 /usr/share/man/man1/aria_chk.1.gz /usr/share/man/man1/aria_dump_log.1.gz /usr/share/man/man1/aria_ftdump.1.gz /usr/share/man/man1/aria_pack.1.gz /usr/share/man/man1/aria_read_log.1.gz /usr/share/man/man1/galera_new_cluster.1.gz /usr/share/man/man1/galera_recovery.1.gz /usr/share/man/man1/innochecksum.1.gz /usr/share/man/man1/mariabackup.1.gz /usr/share/man/man1/mariadb-service-convert.1.gz /usr/share/man/man1/mbstream.1.gz /usr/share/man/man1/my_print_defaults.1.gz /usr/share/man/man1/myisam_ftdump.1.gz /usr/share/man/man1/myisamchk.1.gz /usr/share/man/man1/myisamlog.1.gz /usr/share/man/man1/myisampack.1.gz /usr/share/man/man1/mysql.server.1.gz /usr/share/man/man1/mysql_convert_table_format.1.gz /usr/share/man/man1/mysql_fix_extensions.1.gz /usr/share/man/man1/mysql_install_db.1.gz /usr/share/man/man1/mysql_ldb.1.gz /usr/share/man/man1/mysql_secure_installation.1.gz /usr/share/man/man1/mysql_setpermission.1.gz /usr/share/man/man1/mysql_tzinfo_to_sql.1.gz /usr/share/man/man1/mysql_upgrade.1.gz /usr/share/man/man1/mysqld_multi.1.gz /usr/share/man/man1/mysqld_safe.1.gz /usr/share/man/man1/mysqld_safe_helper.1.gz /usr/share/man/man1/mysqldumpslow.1.gz /usr/share/man/man1/mysqlhotcopy.1.gz /usr/share/man/man1/perror.1.gz /usr/share/man/man1/replace.1.gz /usr/share/man/man1/resolve_stack_dump.1.gz /usr/share/man/man1/resolveip.1.gz /usr/share/man/man1/wsrep_sst_common.1.gz /usr/share/man/man1/wsrep_sst_mariabackup.1.gz /usr/share/man/man1/wsrep_sst_mysqldump.1.gz /usr/share/man/man1/wsrep_sst_rsync.1.gz /usr/share/man/man1/wsrep_sst_rsync_wan.1.gz /usr/share/man/man1/wsrep_sst_xtrabackup-v2.1.gz /usr/share/man/man1/wsrep_sst_xtrabackup.1.gz /usr/share/man/man8 /usr/share/man/man8/mysqld.8.gz /usr/share/mysql /usr/share/mysql/binary-configure /usr/share/mysql/czech /usr/share/mysql/czech/errmsg.sys /usr/share/mysql/danish /usr/share/mysql/danish/errmsg.sys /usr/share/mysql/dutch /usr/share/mysql/dutch/errmsg.sys /usr/share/mysql/english /usr/share/mysql/english/errmsg.sys /usr/share/mysql/errmsg-utf8.txt /usr/share/mysql/estonian /usr/share/mysql/estonian/errmsg.sys /usr/share/mysql/fill_help_tables.sql /usr/share/mysql/french /usr/share/mysql/french/errmsg.sys /usr/share/mysql/german /usr/share/mysql/german/errmsg.sys /usr/share/mysql/greek /usr/share/mysql/greek/errmsg.sys /usr/share/mysql/hindi /usr/share/mysql/hindi/errmsg.sys /usr/share/mysql/hungarian /usr/share/mysql/hungarian/errmsg.sys /usr/share/mysql/install_spider.sql /usr/share/mysql/italian /usr/share/mysql/italian/errmsg.sys /usr/share/mysql/japanese /usr/share/mysql/japanese/errmsg.sys /usr/share/mysql/korean /usr/share/mysql/korean/errmsg.sys /usr/share/mysql/magic /usr/share/mysql/maria_add_gis_sp.sql /usr/share/mysql/maria_add_gis_sp_bootstrap.sql /usr/share/mysql/my-huge.cnf /usr/share/mysql/my-innodb-heavy-4G.cnf /usr/share/mysql/my-large.cnf /usr/share/mysql/my-medium.cnf /usr/share/mysql/my-small.cnf /usr/share/mysql/mysql-log-rotate /usr/share/mysql/mysql.server /usr/share/mysql/mysql_performance_tables.sql /usr/share/mysql/mysql_system_tables.sql /usr/share/mysql/mysql_system_tables_data.sql /usr/share/mysql/mysql_test_data_timezone.sql /usr/share/mysql/mysql_test_db.sql /usr/share/mysql/mysql_to_mariadb.sql /usr/share/mysql/mysqld_multi.server /usr/share/mysql/norwegian /usr/share/mysql/norwegian-ny /usr/share/mysql/norwegian-ny/errmsg.sys /usr/share/mysql/norwegian/errmsg.sys /usr/share/mysql/policy /usr/share/mysql/policy/apparmor /usr/share/mysql/policy/apparmor/README /usr/share/mysql/policy/apparmor/usr.sbin.mysqld /usr/share/mysql/policy/apparmor/usr.sbin.mysqld.local /usr/share/mysql/policy/selinux /usr/share/mysql/policy/selinux/README /usr/share/mysql/policy/selinux/mariadb-server.fc /usr/share/mysql/policy/selinux/mariadb-server.te /usr/share/mysql/policy/selinux/mariadb.pp /usr/share/mysql/policy/selinux/mariadb.te /usr/share/mysql/polish /usr/share/mysql/polish/errmsg.sys /usr/share/mysql/portuguese /usr/share/mysql/portuguese/errmsg.sys /usr/share/mysql/romanian /usr/share/mysql/romanian/errmsg.sys /usr/share/mysql/russian /usr/share/mysql/russian/errmsg.sys /usr/share/mysql/serbian /usr/share/mysql/serbian/errmsg.sys /usr/share/mysql/slovak /usr/share/mysql/slovak/errmsg.sys /usr/share/mysql/spanish /usr/share/mysql/spanish/errmsg.sys /usr/share/mysql/swedish /usr/share/mysql/swedish/errmsg.sys /usr/share/mysql/systemd /usr/share/mysql/systemd/mariadb.service /usr/share/mysql/systemd/mariadb@.service /usr/share/mysql/systemd/use_galera_new_cluster.conf /usr/share/mysql/ukrainian /usr/share/mysql/ukrainian/errmsg.sys /usr/share/mysql/wsrep.cnf /usr/share/mysql/wsrep_notify

启动服务和查看端口

[root@localhost ~]# systemctl enable --now mariadb Created symlink from /etc/systemd/system/mysql.service to /usr/lib/systemd/system/mariadb.service. Created symlink from /etc/systemd/system/mysqld.service to /usr/lib/systemd/system/mariadb.service. Created symlink from /etc/systemd/system/multi-user.target.wants/mariadb.service to /usr/lib/systemd/system/mariadb.service. ###################### [root@localhost ~]# ss -ntl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 80 [::]:3306 [::]:*

查看客户端包

[root@localhost ~]# which mysql /usr/bin/mysql [root@localhost ~]# rpm -qf /usr/bin/mysql MariaDB-client-10.2.32-1.el7.centos.x86_64

连接数据库

# 默认没有密码 [root@localhost ~]# mysql -uroot -p Enter password: Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 8 Server version: 10.2.32-MariaDB MariaDB Server 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)]> exit Bye ############################################################################ [root@localhost ~]# mysql Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 9 Server version: 10.2.32-MariaDB MariaDB Server 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)]> exit Bye

Mariadb客户端相关命令

MariaDB [(none)]> \h General information about MariaDB can be found at http://mariadb.org List of all MySQL commands: Note that all text commands must be first on line and end with ';' ? (\?) Synonym for `help'. clear (\c) Clear the current input statement. connect (\r) Reconnect to the server. Optional arguments are db and host. delimiter (\d) Set statement delimiter. edit (\e) Edit command with $EDITOR. ego (\G) Send command to mysql server, display result vertically. exit (\q) Exit mysql. Same as quit. go (\g) Send command to mysql server. help (\h) Display this help. nopager (\n) Disable pager, print to stdout. notee (\t) Don't write into outfile. pager (\P) Set PAGER [to_pager]. Print the query results via PAGER. print (\p) Print current command. prompt (\R) Change your mysql prompt. quit (\q) Quit mysql. rehash (\#) Rebuild completion hash. source (\.) Execute an SQL script file. Takes a file name as an argument. status (\s) Get status information from the server. system (\!) Execute a system shell command. tee (\T) Set outfile [to_outfile]. Append everything into given outfile. use (\u) Use another database. Takes database name as argument. charset (\C) Switch to another charset. Might be needed for processing binlog with multi-byte charsets. warnings (\W) Show warnings after every statement. nowarning (\w) Don't show warnings after every statement. For server side help, type 'help contents'

查看服务器信息

MariaDB [(none)]> \s -------------- mysql Ver 15.1 Distrib 10.2.32-MariaDB, for Linux (x86_64) using readline 5.1 Connection id: 10 Current database: # 账号名加@客户端主机地址 Current user: root@localhost SSL: Not in use Current pager: stdout Using outfile: '' Using delimiter: ; Server: MariaDB Server version: 10.2.32-MariaDB MariaDB Server Protocol version: 10 Connection: Localhost via UNIX socket Server characterset: latin1 Db characterset: latin1 Client characterset: utf8 Conn. characterset: utf8 # 在同一台电脑上利用socket套接字文件进行通信 UNIX socket: /var/lib/mysql/mysql.sock Uptime: 5 min 55 sec Threads: 7 Questions: 8 Slow queries: 0 Opens: 17 Flush tables: 1 Open tables: 11 Queries per second avg: 0.022 --------------

查看套接字文件/var/lib/mysql/mysql.sock

[root@localhost ~]# ll /var/lib/mysql/mysql.sock srwxrwxrwx 1 mysql mysql 0 Jun 22 20:21 /var/lib/mysql/mysql.sock # 在同一台主机中利用套接字文件，可以省去tcp协议的封装与解封装的过程 # 真正跨网络还是应该走tcp协议

实例 instance

多实例的数据库错开端口号，一般测试环境使用

查看数据库文件/var/lib/mysql

[root@localhost ~]# cd /var/lib/mysql/ [root@localhost mysql]# ls aria_log.00000001 ibdata1 ibtmp1 mysql tc.log aria_log_control ib_logfile0 localhost.pid mysql.sock test ib_buffer_pool ib_logfile1 multi-master.info performance_schema [root@localhost mysql]# cd mysql/ [root@localhost mysql]# ls columns_priv.frm help_category.MYD plugin.MYD tables_priv.MYI columns_priv.MYD help_category.MYI plugin.MYI table_stats.frm columns_priv.MYI help_keyword.frm proc.frm table_stats.MYD column_stats.frm help_keyword.MYD proc.MYD table_stats.MYI column_stats.MYD help_keyword.MYI proc.MYI time_zone.frm column_stats.MYI help_relation.frm procs_priv.frm time_zone_leap_second.frm db.frm help_relation.MYD procs_priv.MYD time_zone_leap_second.MYD db.MYD help_relation.MYI procs_priv.MYI time_zone_leap_second.MYI db.MYI help_topic.frm proxies_priv.frm time_zone.MYD db.opt help_topic.MYD proxies_priv.MYD time_zone.MYI event.frm help_topic.MYI proxies_priv.MYI time_zone_name.frm event.MYD host.frm roles_mapping.frm time_zone_name.MYD event.MYI host.MYD roles_mapping.MYD time_zone_name.MYI func.frm host.MYI roles_mapping.MYI time_zone_transition.frm func.MYD index_stats.frm servers.frm time_zone_transition.MYD func.MYI index_stats.MYD servers.MYD time_zone_transition.MYI general_log.CSM index_stats.MYI servers.MYI time_zone_transition_type.frm general_log.CSV innodb_index_stats.frm slow_log.CSM time_zone_transition_type.MYD general_log.frm innodb_index_stats.ibd slow_log.CSV time_zone_transition_type.MYI gtid_slave_pos.frm innodb_table_stats.frm slow_log.frm user.frm gtid_slave_pos.ibd innodb_table_stats.ibd tables_priv.frm user.MYD help_category.frm plugin.frm tables_priv.MYD user.MYI

同一个表有着不同的文件格式后缀，对应的是不同的数据库引擎

MYD——>MyISAM

查看服务器端数据库

指定访问数据库

# use 关键字命令可以不加分号; MariaDB [(none)]> use mysql Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed MariaDB [mysql]>

查看表格

查看user表格

MariaDB [mysql]> desc user; +------------------------+-----------------------------------+------+-----+----------+-------+ | Field | Type | Null | Key | Default | Extra | +------------------------+-----------------------------------+------+-----+----------+-------+ | Host | char(60) | NO | PRI | | | | User | char(80) | NO | PRI | | | | Password | char(41) | NO | | | | | Select_priv | enum('N','Y') | NO | | N | | | Insert_priv | enum('N','Y') | NO | | N | | | Update_priv | enum('N','Y') | NO | | N | | | Delete_priv | enum('N','Y') | NO | | N | | | Create_priv | enum('N','Y') | NO | | N | | | Drop_priv | enum('N','Y') | NO | | N | | | Reload_priv | enum('N','Y') | NO | | N | | | Shutdown_priv | enum('N','Y') | NO | | N | | | Process_priv | enum('N','Y') | NO | | N | | | File_priv | enum('N','Y') | NO | | N | | | Grant_priv | enum('N','Y') | NO | | N | | | References_priv | enum('N','Y') | NO | | N | | | Index_priv | enum('N','Y') | NO | | N | | | Alter_priv | enum('N','Y') | NO | | N | | | Show_db_priv | enum('N','Y') | NO | | N | | | Super_priv | enum('N','Y') | NO | | N | | | Create_tmp_table_priv | enum('N','Y') | NO | | N | | | Lock_tables_priv | enum('N','Y') | NO | | N | | | Execute_priv | enum('N','Y') | NO | | N | | | Repl_slave_priv | enum('N','Y') | NO | | N | | | Repl_client_priv | enum('N','Y') | NO | | N | | | Create_view_priv | enum('N','Y') | NO | | N | | | Show_view_priv | enum('N','Y') | NO | | N | | | Create_routine_priv | enum('N','Y') | NO | | N | | | Alter_routine_priv | enum('N','Y') | NO | | N | | | Create_user_priv | enum('N','Y') | NO | | N | | | Event_priv | enum('N','Y') | NO | | N | | | Trigger_priv | enum('N','Y') | NO | | N | | | Create_tablespace_priv | enum('N','Y') | NO | | N | | | ssl_type | enum('','ANY','X509','SPECIFIED') | NO | | | | | ssl_cipher | blob | NO | | NULL | | | x509_issuer | blob | NO | | NULL | | | x509_subject | blob | NO | | NULL | | | max_questions | int(11) unsigned | NO | | 0 | | | max_updates | int(11) unsigned | NO | | 0 | | | max_connections | int(11) unsigned | NO | | 0 | | | max_user_connections | int(11) | NO | | 0 | | | plugin | char(64) | NO | | | | | authentication_string | text | NO | | NULL | | | password_expired | enum('N','Y') | NO | | N | | | is_role | enum('N','Y') | NO | | N | | | default_role | char(80) | NO | | | | | max_statement_time | decimal(12,6) | NO | | 0.000000 | | +------------------------+-----------------------------------+------+-----+----------+-------+ 46 rows in set (0.00 sec)

查看user、host、password三个字段

有一些user为空，密码也为空，存在安全问题

user为空意思是可以随便填写用户名

安全加固/usr/bin/mysql_secure_installation

[root@localhost ~]# ll /usr/bin/mysql_secure_installation -rwxr-xr-x 1 root root 12527 May 8 20:36 /usr/bin/mysql_secure_installation # 该文件是一个脚本 # 运行该脚本 [root@localhost ~]# mysql_secure_installation NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY! In order to log into MariaDB to secure it, we'll need the current password for the root user. If you've just installed MariaDB, and you haven't set the root password yet, the password will be blank, so you should just press enter here. Enter current password for root (enter for none): OK, successfully used password, moving on... Setting the root password ensures that nobody can log into the MariaDB root user without the proper authorisation. Set root password? [Y/n] yes New password: Re-enter new password: Password updated successfully! Reloading privilege tables.. ... Success! By default, a MariaDB installation has an anonymous user, allowing anyone to log into MariaDB 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? [Y/n] 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? [Y/n] y ... Success! By default, MariaDB 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? [Y/n] 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? [Y/n] y ... Success! Cleaning up... All done! If you've completed all of the above steps, your MariaDB installation should now be secure. Thanks for using MariaDB!

运行网络远程登录

# mariadb要远程登录需要另外设置远程登录账户

MariaDB程序

客户端程序： mysql: 交互式的CLI工具mysqldump：备份工具，基于mysql协议向mysqld发起查询请求，并将查得的所有数据转换成insert等写操作语句保存文本文件中mysqladmin：基于mysql协议管理mysqldmysqlimport：数据导入工具 MyISAM存储引擎的管理工具： myisamchk：检查MyISAM库myisampack：打包MyISAM表，只读服务器端程序 mysqld_safemysqldmysqld_multi 多实例，示例：mysqld_multi --example

mysqladmin 说明

[root@localhost ~]# mysqladmin --help mysqladmin Ver 9.1 Distrib 10.2.32-MariaDB, for Linux on x86_64 Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Administration program for the mysqld daemon. Usage: mysqladmin [OPTIONS] command command.... Default options are read from the following files in the given order: /etc/my.cnf ~/.my.cnf The following groups are read: mysqladmin client client-server client-mariadb The following options may be given as the first argument: --print-defaults Print the program argument list and exit. --no-defaults Don't read default options from any option file. The following specify which files/extra groups are read (specified before remaining options): --defaults-file=# Only read default options from the given file #. --defaults-extra-file=# Read this file after the global files are read. --defaults-group-suffix=# Additionally read default groups with # appended as a suffix. -c, --count=# Number of iterations to make. This works with -i (--sleep) only. --debug-check Check memory and open file usage at exit. --debug-info Print some debug info at exit. -f, --force Don't ask for confirmation on drop database; with multiple commands, continue even if an error occurs. -C, --compress Use compression in server/client protocol. --character-sets-dir=name Directory for character set files. --default-character-set=name Set the default character set. -?, --help Display this help and exit. -h, --host=name Connect to host. -l, --local Local command, don't write to binlog. -b, --no-beep Turn off beep on error. -p, --password[=name] Password to use when connecting to server. If password is not given it's asked from the tty. -P, --port=# Port number to use for connection or 0 for default to, in order of preference, my.cnf, $MYSQL_TCP_PORT, /etc/services, built-in default (3306). --protocol=name The protocol to use for connection (tcp, socket, pipe, memory). -r, --relative Show difference between current and previous values when used with -i. Currently only works with extended-status. -s, --silent Silently exit if one can't connect to server. -S, --socket=name The socket file to use for connection. -i, --sleep=# Execute commands repeatedly with a sleep between. --ssl Enable SSL for connection (automatically enabled with other flags). --ssl-ca=name CA file in PEM format (check OpenSSL docs, implies --ssl). --ssl-capath=name CA directory (check OpenSSL docs, implies --ssl). --ssl-cert=name X509 cert in PEM format (implies --ssl). --ssl-cipher=name SSL cipher to use (implies --ssl). --ssl-key=name X509 key in PEM format (implies --ssl). --ssl-crl=name Certificate revocation list (implies --ssl). --ssl-crlpath=name Certificate revocation list path (implies --ssl). --ssl-verify-server-cert Verify server's "Common Name" in its cert against hostname used when connecting. This option is disabled by default. -u, --user=name User for login if not current user. -v, --verbose Write more information. -V, --version Output version information and exit. -E, --vertical Print output vertically. Is similar to --relative, but prints output vertically. -w, --wait[=#] Wait and retry if connection is down. --connect-timeout=# --shutdown-timeout=# --plugin-dir=name Directory for client-side plugins. --default-auth=name Default authentication client-side plugin to use. Variables (--variable-name=value) and boolean options {FALSE|TRUE} Value (after reading options) --------------------------------- ---------------------------------------- count 0 debug-check FALSE debug-info FALSE force FALSE compress FALSE character-sets-dir (No default value) default-character-set auto host (No default value) local FALSE no-beep FALSE port 0 relative FALSE socket (No default value) sleep 0 ssl FALSE ssl-ca (No default value) ssl-capath (No default value) ssl-cert (No default value) ssl-cipher (No default value) ssl-key (No default value) ssl-crl (No default value) ssl-crlpath (No default value) ssl-verify-server-cert FALSE user (No default value) verbose FALSE vertical FALSE connect-timeout 43200 shutdown-timeout 3600 plugin-dir (No default value) default-auth (No default value) Where command is a one or more of: (Commands may be shortened) create databasename Create a new database debug Instruct server to write debug information to log drop databasename Delete a database and all its tables extended-status Gives an extended status message from the server flush-all-statistics Flush all statistics tables flush-all-status Flush status and statistics flush-client-statistics Flush client statistics flush-hosts Flush all cached hosts flush-index-statistics Flush index statistics flush-logs Flush all logs flush-privileges Reload grant tables (same as reload) flush-binary-log Flush binary log flush-engine-log Flush engine log(s) flush-error-log Flush error log flush-general-log Flush general log flush-relay-log Flush relay log flush-slow-log Flush slow query log flush-status Clear status variables flush-table-statistics Clear table statistics flush-tables Flush all tables flush-threads Flush the thread cache flush-user-statistics Flush user statistics flush-user-resources Flush user resources kill id,id,... Kill mysql threads password [new-password] Change old password to new-password in current format old-password [new-password] Change old password to new-password in old format ping Check if mysqld is alive processlist Show list of active threads in server reload Reload grant tables refresh Flush all tables and close and open logfiles shutdown Take server down status Gives a short status message from the server start-slave Start slave stop-slave Stop slave variables Prints variables available version Get version info from server

检查数据库是否正常

[root@localhost ~]# mysqladmin -uroot -p ping Enter password: mysqld is alive

关闭数据库

两种方法

systemctl stop mariadb mysqladmin shutdown

注意：千万不要通过杀进程方式关闭服务器

更改口令密码

[root@localhost ~]# mysqladmin -uroot -proot password New password: Confirm new password: # 我将原本的口令改了

暴力破解口令

# 删除/var/lib/mysql/文件夹下所有内容 # 再重启mariadb服务 # mysql会恢复出始值

查看mariadb-server安装脚本

[root@localhost ~]# rpm -q --scripts MariaDB-server preinstall scriptlet (using /bin/sh): # Check if we can safely upgrade. An upgrade is only safe if it's from one # of our RPMs in the same version family. installed=`rpm -q --whatprovides mysql-server 2> /dev/null` if [ $? -eq 0 -a -n "$installed" ]; then installed=`echo "$installed"|sed -n 1p` vendor=`rpm -q --queryformat='%{VENDOR}' "$installed" 2>&1 | sed 's/Monty Program AB/MariaDB Foundation/'` version=`rpm -q --queryformat='%{VERSION}' "$installed" 2>&1` myvendor='MariaDB Foundation' myversion='10.2.32' old_family=`echo $version | sed -n -e 's,^$[1-9][0-9]*\.[0-9][0-9]*$\..*$,\1,p'` new_family=`echo $myversion | sed -n -e 's,^$[1-9][0-9]*\.[0-9][0-9]*$\..*$,\1,p'` [ -z "$vendor" ] && vendor='<unknown>' [ -z "$old_family" ] && old_family="<unrecognized version $version>" [ -z "$new_family" ] && new_family="<bad package specification: version $myversion>" error_text= if [ "$vendor" != "$myvendor" ]; then error_text="$error_text The current MariaDB server package is provided by a different vendor ($vendor) than $myvendor. Some files may be installed to different locations, including log files and the service startup script in /etc/init.d/. " fi if [ "$old_family" != "$new_family" ]; then error_text="$error_text Upgrading directly from MySQL $old_family to MariaDB $new_family may not be safe in all cases. A manual dump and restore using mysqldump is recommended. It is important to review the MariaDB manual's Upgrading section for version-specific incompatibilities. " fi if [ -n "$error_text" ]; then cat <<HERE >&2 ****************************************************************** A MySQL or MariaDB server package ($installed) is installed. $error_text A manual upgrade is required. - Ensure that you have a complete, working backup of your data and my.cnf files - Shut down the MySQL server cleanly - Remove the existing MySQL packages. Usually this command will list the packages you should remove: rpm -qa | grep -i '^mysql-' You may choose to use 'rpm --nodeps -ev <package-name>' to remove the package which contains the mysqlclient shared library. The library will be reinstalled by the MariaDB-shared package. - Install the new MariaDB packages supplied by $myvendor - Ensure that the MariaDB server is started - Run the 'mysql_upgrade' program This is a brief description of the upgrade process. Important details can be found in the MariaDB manual, in the Upgrading section. ****************************************************************** HERE exit 1 fi fi postinstall scriptlet (using /bin/sh): if [ -f /usr/lib/systemd/system/mariadb.service -a -x /usr/bin/systemctl ]; then systemd_conf=/etc/systemd/system/mariadb.service.d/migrated-from-my.cnf-settings.conf if [ -x /usr/bin/mariadb-service-convert -a ! -f "${systemd_conf}" ]; then # Either fresh install or upgrade non-systemd -> systemd mkdir -p /etc/systemd/system/mariadb.service.d /usr/bin/mariadb-service-convert > "${systemd_conf}" # Make sure old possibly non-systemd instance is down if [ $1 = 2 ]; then SYSTEMCTL_SKIP_REDIRECT=1 /etc/init.d/mysql stop >/dev/null 2>&1 || : systemctl start mariadb >/dev/null 2>&1 || : fi systemctl enable mariadb.service >/dev/null 2>&1 || : fi fi # Make MySQL start/shutdown automatically when the machine does it. if [ $1 = 1 ] ; then if [ -x /usr/bin/systemctl ] ; then /usr/bin/systemctl daemon-reload >/dev/null 2>&1 || : /usr/bin/systemctl preset mariadb.service >/dev/null 2>&1 || : elif [ -x /sbin/chkconfig ] ; then /sbin/chkconfig --add mysql fi basedir=`/usr/bin/my_print_defaults --mysqld|sed -ne 's/^--basedir=//p'|tail -1` if [ -z "$basedir" ] ; then basedir=/usr fi datadir=`/usr/bin/my_print_defaults --mysqld|sed -ne 's/^--datadir=//p'|tail -1` if [ -z "$datadir" ] ; then datadir=/var/lib/mysql else # datadir may be relative to a basedir! if ! expr $datadir : / > /dev/null; then datadir=$basedir/$datadir fi fi # Create a MySQL user and group. Do not report any problems if it already # exists. groupadd -r mysql 2> /dev/null || true useradd -M -r --home $datadir --shell /sbin/nologin --comment "MySQL server" --gid mysql mysql 2> /dev/null || true # The user may already exist, make sure it has the proper group nevertheless (BUG#12823) usermod --gid mysql mysql 2> /dev/null || true # Temporary Workaround for MDEV-11386 - will be corrected in Advance Toolchain 10.0-3 and 8.0-8 for ldconfig in /opt/at*/sbin/ldconfig; do test -x $ldconfig && $ldconfig done # Change permissions so that the user that will run the MySQL daemon # owns all database files. chown -R -f mysql:mysql $datadir if [ ! -e $datadir/mysql ]; then # Create data directory mkdir -p $datadir # Initiate databases /usr/bin/mysql_install_db --rpm --user=mysql fi # Change permissions again to fix any new files. chown -R mysql:mysql $datadir # Fix permissions for the permission database so that only the user # can read them. chmod -R og-rw $datadir/mysql fi # install SELinux files - but don't override existing ones SETARGETDIR=/etc/selinux/targeted/src/policy SEDOMPROG=$SETARGETDIR/domains/program SECONPROG=$SETARGETDIR/file_contexts/program if [ -x /usr/sbin/semodule ] ; then /usr/sbin/semodule -i /usr/share/mysql/policy/selinux/mariadb.pp fi if [ -x sbin/restorecon ] ; then sbin/restorecon -R var/lib/mysql fi preuninstall scriptlet (using /bin/sh): if [ $1 = 0 ] ; then # Stop MySQL before uninstalling it # Don't start it automatically anymore if [ -x /usr/bin/systemctl ] ; then /usr/bin/systemctl stop mariadb.service > /dev/null 2>&1 /usr/bin/systemctl disable mariadb.service > /dev/null 2>&1 fi if [ -x /etc/init.d/mysql ] ; then /etc/init.d/mysql stop > /dev/null fi if [ -x /sbin/chkconfig ] ; then /sbin/chkconfig --del mysql > /dev/null 2>&1 || : fi fi # We do not remove the mysql user since it may still own a lot of # database files. postuninstall scriptlet (using /bin/sh): if [ $1 -ge 1 ]; then # request the server restart mkdir -p /var/lib/rpm-state/mariadb echo > /var/lib/rpm-state/mariadb/need-restart fi if [ $1 = 0 ] ; then if [ -x /usr/bin/systemctl ] ; then /usr/bin/systemctl daemon-reload > /dev/null 2>&1 fi fi posttrans scriptlet (using /bin/sh): if [ -r /var/lib/rpm-state/mariadb/need-restart ] ; then rm /var/lib/rpm-state/mariadb/need-restart if [ -x /usr/bin/systemctl ] ; then /usr/bin/systemctl daemon-reload > /dev/null 2>&1 /usr/bin/systemctl try-restart mariadb.service > /dev/null 2>&1 elif /etc/init.d/mysql status > /dev/null 2>&1; then # only restart the server if it was alredy running /etc/init.d/mysql restart fi fi

用户账号

mysql用户账号由两部分组成： ‘USERNAME’@'HOST‘ 说明： HOST限制此用户可通过哪些远程主机连接mysql服务器支持使用通配符： % 匹配任意长度的任意字符172.16.0.0/255.255.0.0 或 172.16.%.%_ 匹配任意单个字符

mysql的配置文件

[root@localhost ~]# cat /etc/my.cnf # # This group is read both both by the client and the server # use it for options that affect everything # [client-server] # # include *.cnf from the config directory # !includedir /etc/my.cnf.d #也可以放入 /etc/my.cnf.d文件夹下 [root@localhost ~]# tree /etc/my.cnf.d /etc/my.cnf.d ├── enable_encryption.preset ├── mysql-clients.cnf └── server.cnf 0 directories, 3 files

查看mysql-clients.cnf

[root@localhost ~]# cat /etc/my.cnf.d/mysql-clients.cnf # # These groups are read by MariaDB command-line tools # Use it for options that affect only one utility # 每个客户端都具有自己的独立配置信息 [mysql] [mysql_upgrade] [mysqladmin] [mysqlbinlog] [mysqlcheck] [mysqldump] [mysqlimport] [mysqlshow] [mysqlslap]

维护数据库时，关闭3306端口，仅仅本地连接

vim /etc/my.cnf [mysqld] skip-networking=1 #关闭网络连接，只侦听本地客户端，所有和服务器的交互都通过一个socket实现，socket的配置存放在/var/lib/mysql/mysql.sock）可在/etc/my.cnf修改

mysql客户端可用选项：

-A, --no-auto-rehash 禁止补全-u, --user= 用户名,默认为root-h, --host= 服务器主机,默认为localhost-p, --passowrd= 用户密码,建议使用-p,默认为空密码-P, --port= 服务器端口-S, --socket= 指定连接socket文件路径-D, --database= 指定默认数据库-C, --compress 启用压缩-e “SQL“ 执行SQL命令-V, --version 显示版本-v --verbose 显示详细信息–print-defaults 获取程序默认使用的配置

socket地址

服务器监听的两种socket地址： ip socket: 监听在tcp的3306端口，支持远程通信unix sock: 监听在sock文件上，仅支持本机通信如：/var/lib/mysql/mysql.sock)说明：host为localhost,127.0.0.1时自动使用unix sock

显示当前数据库版本号

MariaDB [(none)]> select version(); +-----------------+ | version() | +-----------------+ | 10.2.32-MariaDB | +-----------------+ 1 row in set (0.00 sec)

二进制安装(区别源码编译)

二进制格式安装过程

(1) 准备用户 groupadd -r -g 306 mysql useradd -r -g 306 -u 306 –d /data/mysql mysql (2) 准备数据目录，建议使用逻辑卷 mkdir /data/mysql chown mysql:mysql /data/mysql (3) 准备二进制程序 tar xf mariadb-VERSION-linux-x86_64.tar.gz -C /usr/local # 解压缩必须指定该位置 cd /usr/local ln -sv mariadb-VERSION mysql chown -R root:mysql /usr/local/mysql/ (4) 准备配置文件 mkdir /etc/mysql/ cp support-files/my-large.cnf /etc/mysql/my.cnf #[mysqld]中添加三个选项： datadir = /data/mysql innodb_file_per_table = on skip_name_resolve = on #禁止主机名解析，建议使用 (5)创建数据库文件 cd /usr/local/mysql/ ./scripts/mysql_install_db --datadir=/data/mysql --user=mysql (6)准备服务脚本，并启动服务 cp ./support-files/mysql.server /etc/rc.d/init.d/mysqld chkconfig --add mysqld service mysqld start # centos 6 的用法 (7)PATH路径 echo ‘PATH=/user/local/mysql/bin:$PATH’ > /etc/profile.d/mysql (8)安全初始化 /user/local/mysql/bin/mysql_secure_installation

实验

目标：将数据安装在/data/mysql文件中

创建目录

[root@localhost ~]# mkdir -p /data/mysql/ [root@localhost ~]# useradd -r -s /sbin/nologin -d /data/mysql/ mysql # 不加-m强制生成家目录的选项，因为这个选项会在目录下生成一下.bash开头的文件，不符合我们的要求

解压缩二进制文件

tar xf mariadb-VERSION-linux-x86_64.tar.gz -C /usr/local [root@localhost ~]# cd /usr/local/ [root@localhost /usr/local]# ls bin games lib libexec sbin src etc include lib64 mariadb-10.2.25-linux-x86_64 share [root@localhost /usr/local]# ln -s mariadb-10.2.25-linux-x86_64/ mysql [root@localhost /usr/local]# ll lrwxrwxrwx 1 root root 29 Jun 25 17:42 mysql -> mariadb-10.2.25-linux-x86_64/ [root@localhost /usr/local]# ll mysql/ total 176 drwxr-xr-x 2 1021 1004 4096 Mar 15 2019 bin -rw-r--r-- 1 1021 1004 17987 Jun 15 2019 COPYING -rw-r--r-- 1 1021 1004 2354 Jun 15 2019 CREDITS drwxrwxr-x 3 1021 1004 18 Jun 15 2019 data -rw-r--r-- 1 1021 1004 8245 Jun 15 2019 EXCEPTIONS-CLIENT drwxrwxr-x 3 1021 1004 19 Jun 15 2019 include -rw-r--r-- 1 1021 1004 8694 Jun 15 2019 INSTALL-BINARY drwxr-xr-x 5 1021 1004 335 Mar 15 2019 lib drwxrwxr-x 4 1021 1004 30 Jun 15 2019 man drwxrwxr-x 11 1021 1004 4096 Jun 15 2019 mysql-test -rw-r--r-- 1 1021 1004 2843 Jun 15 2019 README.md -rw-r--r-- 1 1021 1004 19477 Jun 15 2019 README-wsrep drwxrwxr-x 2 1021 1004 30 Jun 15 2019 scripts drwxrwxr-x 32 1021 1004 4096 Jun 15 2019 share drwxrwxr-x 4 1021 1004 4096 Jun 15 2019 sql-bench drwxrwxr-x 3 1021 1004 275 Jun 15 2019 support-files -rw-r--r-- 1 1021 1004 86263 Jun 15 2019 THIRDPARTY # 发现mysql下的文件所属主与组都有问题，因此需要统一修改 [root@localhost /usr/local]# chown -R root.root mysql/ [root@localhost /usr/local]# ll mysql/ total 176 drwxr-xr-x 2 root root 4096 Mar 15 2019 bin -rw-r--r-- 1 root root 17987 Jun 15 2019 COPYING -rw-r--r-- 1 root root 2354 Jun 15 2019 CREDITS drwxrwxr-x 3 root root 18 Jun 15 2019 data -rw-r--r-- 1 root root 8245 Jun 15 2019 EXCEPTIONS-CLIENT drwxrwxr-x 3 root root 19 Jun 15 2019 include -rw-r--r-- 1 root root 8694 Jun 15 2019 INSTALL-BINARY drwxr-xr-x 5 root root 335 Mar 15 2019 lib drwxrwxr-x 4 root root 30 Jun 15 2019 man drwxrwxr-x 11 root root 4096 Jun 15 2019 mysql-test -rw-r--r-- 1 root root 2843 Jun 15 2019 README.md -rw-r--r-- 1 root root 19477 Jun 15 2019 README-wsrep drwxrwxr-x 2 root root 30 Jun 15 2019 scripts drwxrwxr-x 32 root root 4096 Jun 15 2019 share drwxrwxr-x 4 root root 4096 Jun 15 2019 sql-bench drwxrwxr-x 3 root root 275 Jun 15 2019 support-files -rw-r--r-- 1 root root 86263 Jun 15 2019 THIRDPARTY

初始化脚本

[root@localhost /usr/local/mysql]# ls scripts/ mysql_install_db

源码编译

步骤

安装包

yum install bison bison-devel zlib-devel libcurl-devel libarchive-devel boost-devel gcc gcc-c++ cmake ncurses-devel gnutls-devel libxml2-devel openssl-devel libevent-devel libaio-devel -y

如果编译过程出错，尝试安装此包

yum install libdb-cxx-devel

做准备用户和数据目录

useradd –r –s /sbin/nologin –d /data/mysql/ mysql mkdir /data/mysql chown mysql.mysql /data/mysql tar xvf mariadb-10.2.18.tar.gz

cmake 编译安装

cmake的重要特性之一是其独立于源码(out-of-source)的编译功能，即编译工作可以在另一个指定的目录中而非源码目录中进行，这可以保证源码目录不受任何一次编译的影响，因此在同一个源码树上可以进行多次不同的编译，如针对于不同平台编译编译选项:https://dev.mysql.com/doc/refman/5.7/en/source-configuration-options.html

cd mariadb-10.2.18/ ################################### cmake . \ -DCMAKE_INSTALL_PREFIX=/app/mysql \ -DMYSQL_DATADIR=/data/mysql/ \ -DSYSCONFDIR=/etc/mysql \ -DMYSQL_USER=mysql \ -DWITH_INNOBASE_STORAGE_ENGINE=1 \ -DWITH_ARCHIVE_STORAGE_ENGINE=1 \ -DWITH_BLACKHOLE_STORAGE_ENGINE=1 \ -DWITH_PARTITION_STORAGE_ENGINE=1 \ -DWITHOUT_MROONGA_STORAGE_ENGINE=1 \ -DWITH_DEBUG=0 \ -DWITH_READLINE=1 \ -DWITH_SSL=system \ -DWITH_ZLIB=system \ -DWITH_LIBWRAP=0 \ -DENABLED_LOCAL_INFILE=1 \ -DMYSQL_UNIX_ADDR=/data/mysql/mysql.sock \ -DDEFAULT_CHARSET=utf8 \ -DDEFAULT_COLLATION=utf8_general_ci ########################################### make && make install

提示：如果出错，执行rm -f CMakeCache.txt

准备环境变量

echo 'PATH=/app/mysql/bin:$PATH' > /etc/profile.d/mysql.sh . /etc/profile.d/mysql.sh

生成数据库文件

cd /app/mysql/ scripts/mysql_install_db --datadir=/data/mysql/ --user=mysql

准备配置文件

cp /app/mysql/support-files/my-huge.cnf /etc/my.cnf

准备启动脚本

cp /app/mysql/support-files/mysql.server /etc/init.d/mysqld

启动服务

chkconfig --add mysqld ;service mysqld start

多实例

要求在有限的机器上，跑多个服务器，且彼此独立互不影响

在实验主机上跑3个数据库且端口独立

步骤

在/mysql/{3306,3307,3308}分别实例3个独立的数据库,并建立相应文件目录

[root@localhost ~]# mkdir -pv /mysql/{3306,3307,3308}/{data,bin,log,socket,pid,etc} [root@localhost ~]# tree /mysql/ /mysql/ ├── 3306 │ ├── bin │ ├── data │ ├── etc │ ├── log │ ├── pid │ └── socket ├── 3307 │ ├── bin │ ├── data │ ├── etc │ ├── log │ ├── pid │ └── socket └── 3308 ├── bin ├── data ├── etc ├── log ├── pid └── socket

更改/mysql下的所有所属组和所属主

chown -R mysql.mysql /mysql/

实验前注意关闭已经开启的 mariadb服务

运行mysql的安装脚本mysql_install_db

mysql_install_db --datadir=/mysql/{3306,3307,3308}/data/ --user=mysql

建立配置文件

cp /etc/my.cnf /mysql/3306/etc/ vim /mysql/3306/etc/my.cnf ############################ [mysqld] port=3306 datadir=/mysql/3306/data/ socket=/mysql/3306/socket/mysql.sock symbolic-links=0 [mysqld_safe] log-error=/mysql/3306/log/mariadb.log pid-file=/mysql/3306/pid/mariadb.pid

将配置文件修改好后，复制到3307,3308对应文件夹下，并改好端口

cp /mysql/3306/etc/my.cnf /mysql/3307/etc/ cp /mysql/3306/etc/my.cnf /mysql/3308/etc/ ############################################ sed -i 's/3306/3307/' /mysql/3307/etc/my.cnf sed -i 's/3306/3308/' /mysql/3308/etc/my.cnf

启动脚本

[root@localhost bin]# pwd /mysql/3306/bin [root@localhost bin]# cat mysqld #!/bin/bash port=3306 mysql_user="root" mysql_pwd="" cmd_path="/usr/bin" mysql_basedir="/mysql" mysql_sock="${mysql_basedir}/${port}/socket/mysql.sock" function_start_mysql() { if [ ! -e "$mysql_sock" ];then printf "Are you OK? Starting MySQL...\n" ${cmd_path}/mysqld_safe --defaults-file=${mysql_basedir}/${port}/etc/my.cnf &> /dev/null & else printf "Are you OK? MySQL is running...\n" exit fi } function_stop_mysql() { if [ ! -e "$mysql_sock" ];then printf "Are you OK? MySQL is stopped...\n" exit else printf "Are you OK? Stoping MySQL...\n" ${cmd_path}/mysqladmin -u ${mysql_user} -p${mysql_pwd} -S ${mysql_sock} shutdown fi } function_restart_mysql() { printf "Are you OK? Restarting MySQL...\n" function_stop_mysql sleep 2 function_start_mysql } case $1 in start) function_start_mysql ;; stop) function_stop_mysql ;; restart) function_restart_mysql ;; *) printf "Usage: ${mysql_basedir}/${port}/bin/mysqld {start|stop|restart}\n" esac cp mysqld /mysql/3307/bin/ cp mysqld /mysql/3308/bin/ ########################## sed -i 's/3306/3307/' /mysql/3307/bin/mysqld sed -i 's/3306/3308/' /mysql/3308/bin/mysqld

启动服务

[root@localhost bin]# /mysql/3306/bin/mysqld start Are you OK? Starting MySQL... [root@localhost bin]# /mysql/3307/bin/mysqld start Are you OK? Starting MySQL... [root@localhost bin]# /mysql/3308/bin/mysqld start Are you OK? Starting MySQL... ################################################## [root@localhost bin]# ss -ntl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 *:22 *:* LISTEN 0 100 [::1]:25 [::]:* LISTEN 0 80 [::]:3306 [::]:* LISTEN 0 80 [::]:3307 [::]:* LISTEN 0 80 [::]:3308 [::]:* LISTEN 0 128 [::]:22 [::]:*

测试连接3307

[root@localhost bin]# mysql -S /mysql/3307/socket/mysql.sock Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 8 Server version: 10.2.32-MariaDB MariaDB Server 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)]> status -------------- mysql Ver 15.1 Distrib 10.2.32-MariaDB, for Linux (x86_64) using readline 5.1 Connection id: 8 Current database: Current user: root@localhost SSL: Not in use Current pager: stdout Using outfile: '' Using delimiter: ; Server: MariaDB Server version: 10.2.32-MariaDB MariaDB Server Protocol version: 10 Connection: Localhost via UNIX socket Server characterset: latin1 Db characterset: latin1 Client characterset: utf8 Conn. characterset: utf8 UNIX socket: /mysql/3307/socket/mysql.sock Uptime: 1 min 36 sec Threads: 7 Questions: 4 Slow queries: 0 Opens: 17 Flush tables: 1 Open tables: 11 Queries per second avg: 0.041 --------------

设置口令

mysqladmin -S /mysql/3308/socket/mysql.sock password centos

SQL语句

数据库：database 表：table 行：row 列：column 索引：index 视图：view 用户：user 权限：privilege 存储过程：procedure 存储函数：function 触发器：trigger 事件调度器：event scheduler，任务计划

SQL语句分类：

DDL: Data Defination Language 数据定义语言 CREATE，DROP，ALTER DML: Data Manipulation Language 数据操纵语言 INSERT，DELETE，UPDATE DCL：Data Control Language 数据控制语言 GRANT，REVOKE，COMMIT，ROLLBACK DQL：Data Query Language 数据查询语言 SELECT

SQL语句关键字建议大写

创建数据库

CREATE DATABASE|SCHEMA [IF NOT EXISTS] 'DB_NAME'; CHARACTER SET 'character set name’COLLATE 'collate name'

修改数据库

ALTER DATABASE DB_NAME character set utf8;

删除数据库

DROP DATABASE|SCHEMA [IF EXISTS] 'DB_NAME';

查看支持所有字符集

SHOW CHARACTER SET;

查看支持所有排序规则

SHOW COLLATION;

获取命令使用帮助

mysql> HELP KEYWORD;

查看数据库列表

mysql> SHOW DATABASES;

数据类型

MySql支持多种列类型：

数值类型日期/时间类型字符串(字符)类型https://dev.mysql.com/doc/refman/5.5/en/data-types.html选择正确的数据类型对于获得高性能至关重要，三大原则：更小的通常更好，尽量使用可正确存储数据的最小数据类型简单就好，简单数据类型的操作通常需要更少的CPU周期尽量避免NULL，包含为NULL的列，对MySQL更难优化

整型

tinyint(m) 1个字节范围(-128~127)smallint(m) 2个字节范围(-32768~32767)mediumint(m) 3个字节范围(-8388608~8388607)int(m) 4个字节范围(-2147483648~2147483647)bigint(m) 8个字节范围(±9.22*10的18次方) 加了unsigned，则最大值翻倍，如：tinyint unsigned的取值范围为(0~255) int(m)里的m是表示SELECT查询结果集中的显示宽度，并不影响实际的取值范围，规定了MySQL的一些交互工具（例如MySQL命令行客户端）用来显示字符的个数。对于存储和计算来说，Int(1)和Int(20)是相同的BOOL，BOOLEAN：布尔型，是TINYINT(1)的同义词。zero值被视为假，非zero值视为真

浮点型(float和double)，近似值

float(m,d) 单精度浮点型 8位精度(4字节) m总个数，d小数位double(m,d) 双精度浮点型16位精度(8字节) m总个数，d小数位设一个字段定义为float(6,3)，如果插入一个数123.45678,实际数据库里存的是123.457，但总个数还以实际为准，即6位

定点数

在数据库中存放的是精确值,存为十进制decimal(m,d) 参数m<65 是总个数，d<30且 d<m 是小数位MySQL5.0和更高版本将数字打包保存到一个二进制字符串中（每4个字节存9个数字）。例如，decimal(18,9)小数点两边将各存储9个数字，一共使用9个字节：小数点前的数字用4个字节，小数点后的数字用4个字节，小数点本身占1个字节浮点类型在存储同样范围的值时，通常比decimal使用更少的空间。float使用4个字节存储。double占用8个字节因为需要额外的空间和计算开销，所以应该尽量只在对小数进行精确计算时才使用decimal——例如存储财务数据。但在数据量比较大的时候，可以考虑使用bigint代替decimal

字符串(char,varchar,_text)

char(n) 固定长度，最多255个字符varchar(n) 可变长度，最多65535个字符tinytext 可变长度，最多255个字符text 可变长度，最多65535个字符mediumtext 可变长度，最多2的24次方-1个字符longtext 可变长度，最多2的32次方-1个字符BINARY(M) 固定长度，可存二进制或字符，长度为0-M字节VARBINARY(M) 可变长度，可存二进制或字符，允许长度为0-M字节内建类型：ENUM枚举, SET集合

char和varchar

char(n) 若存入字符数小于n，则以空格补于其后，查询之时再将空格去掉，所以char类型存储的字符串末尾不能有空格，varchar不限于此char(n) 固定长度，char(4)不管是存入几个字符，都将占用4个字节，varchar是存入的实际字符数+1个字节（n< n>255)，所以varchar(4),存入3个字符将占用4个字节char类型的字符串检索速度要比varchar类型的快

varchar和text

varchar可指定n，text不能指定，内部存储varchar是存入的实际字符数+1个字节（n< n>255)，text是实际字符数+2个字节。text类型不能有默认值varchar可直接创建索引，text创建索引要指定前多少个字符。varchar查询速度快于text

二进制数据：BLOB

BLOB和text存储方式不同，TEXT以文本方式存储，英文存储区分大小写，而Blob是以二进制方式存储，不分大小写BLOB存储的数据只能整体读出TEXT可以指定字符集，BLOB不用指定字符集

日期时间类型

date 日期 ‘2008-12-2’time 时间 ‘12:25:36’datetime 日期时间 ‘2008-12-2 22:06:44’timestamp 自动存储记录修改时YEAR(2), YEAR(4)：年份timestamp字段里的时间数据会随其他字段修改的时候自动刷新，这个数据类型的字段可以存放这条记录最后被修改的时间

修饰符

所有类型

NULL 数据列可包含NULL值NOT NULL 数据列不允许包含NULL值DEFAULT 默认值PRIMARY KEY 主键UNIQUE KEY 唯一键CHARACTER SET name 指定一个字符集

数值型

AUTO_INCREMENT 自动递增，适用于整数类型UNSIGNED 无符号

示例：

CREATE TABLE students (id int UNSIGNED NOT NULL PRIMARY KEY,name VARCHAR（20）NOT NULL,age tinyint UNSIGNED); DESC students; CREATE TABLE students2 (id int UNSIGNED NOT NULL ,name VARCHAR(20) NOT NULL,age tinyint UNSIGNED,PRIMARY KEY(id,name));

DML语言

DML: INSERT, DELETE, UPDATE

INSERT：一次插入一行或多行数据语法

INSERT [L OW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name [(col_name,...)] {VALUES | VALUE} ({expr | DEFAULT},...),(...),... [ ON DUPLICATE KEY UPDATE 如果重复更新之 col_name=expr [, col_name=expr] ... ] 简化写法： INSERT tbl_name [(col1,...)] VALUES (val1,...), (val21,...) ################## INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name SET col_name={expr | DEFAULT}, ... [ ON DUPLICATE KEY UPDATE col_name=expr [, col_name=expr] ... ] ################### INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name [(col_name,...)] SELECT ... [ ON DUPLICATE KEY UPDATE col_name=expr [, col_name=expr] ... ] ######################## INSERT INTO students VALUES(1,'tom'，'m'),(2,'alice','f'); INSERT INTO students(id,name) VALUES(3,'jack'),(4,'allen');

UPDATE

UPDATE [LOW_PRIORITY] [IGNORE] table_reference SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ... [WHERE where_condition] [ORDER BY ...] [LIMIT row_count]

注意：这种操作非常危险，且不能恢复，最好执行的是safe update模式

Mysql 选项：-U|–safe-updates| --i-am-a-dummy

将sefe-updates写入Mysql客户端配置文件中

DELETE（清空表，表还在，数据没了）

TRUNCATE TABLE tbl_name; 快速清空表

mysql客户端默认字符集

mariadb服务器端字符集

查看表格的字符集信息

SQL语句DQL单表查询

SELECT

MariaDB [hellodb]> help select; Name: 'SELECT' Description: Syntax: SELECT [ALL | DISTINCT | DISTINCTROW ] [HIGH_PRIORITY] [STRAIGHT_JOIN] [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT] [SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS] select_expr [, select_expr ...] [FROM table_references [WHERE where_condition] [GROUP BY {col_name | expr | position} [ASC | DESC], ... [WITH ROLLUP]] [HAVING where_condition] [ORDER BY {col_name | expr | position} [ASC | DESC], ...] [LIMIT {[offset,] row_count | row_count OFFSET offset}] [PROCEDURE procedure_name(argument_list)] [INTO OUTFILE 'file_name' [CHARACTER SET charset_name] export_options | INTO DUMPFILE 'file_name' | INTO var_name [, var_name]] [FOR UPDATE | LOCK IN SHARE MODE]]

SELECT的小功能

MariaDB [hellodb]> select "hello"; +-------+ | hello | +-------+ | hello | +-------+ 1 row in set (0.00 sec) # echo 功能 MariaDB [hellodb]> select 200*30; +--------+ | 200*30 | +--------+ | 6000 | +--------+ 1 row in set (0.00 sec) # 数字运算

数据库导入

[root@localhost ~]# mysql < hellodb_innodb.sql

查看表内容

查看students表内容

MariaDB [hellodb]> SELECT * FROM students; +-------+---------------+-----+--------+---------+-----------+ | StuID | Name | Age | Gender | ClassID | TeacherID | +-------+---------------+-----+--------+---------+-----------+ | 1 | Shi Zhongyu | 22 | M | 2 | 3 | | 2 | Shi Potian | 22 | M | 1 | 7 | | 3 | Xie Yanke | 53 | M | 2 | 16 | | 4 | Ding Dian | 32 | M | 4 | 4 | | 5 | Yu Yutong | 26 | M | 3 | 1 | | 6 | Shi Qing | 46 | M | 5 | NULL | | 7 | Xi Ren | 19 | F | 3 | NULL | | 8 | Lin Daiyu | 17 | F | 7 | NULL | | 9 | Ren Yingying | 20 | F | 6 | NULL | | 10 | Yue Lingshan | 19 | F | 3 | NULL | | 11 | Yuan Chengzhi | 23 | M | 6 | NULL | | 12 | Wen Qingqing | 19 | F | 1 | NULL | | 13 | Tian Boguang | 33 | M | 2 | NULL | | 14 | Lu Wushuang | 17 | F | 3 | NULL | | 15 | Duan Yu | 19 | M | 4 | NULL | | 16 | Xu Zhu | 21 | M | 1 | NULL | | 17 | Lin Chong | 25 | M | 4 | NULL | | 18 | Hua Rong | 23 | M | 7 | NULL | | 19 | Xue Baochai | 18 | F | 6 | NULL | | 20 | Diao Chan | 19 | F | 7 | NULL | | 21 | Huang Yueying | 22 | F | 6 | NULL | | 22 | Xiao Qiao | 20 | F | 1 | NULL | | 23 | Ma Chao | 23 | M | 4 | NULL | | 24 | Xu Xian | 27 | M | NULL | NULL | | 25 | Sun Dasheng | 100 | M | NULL | NULL | +-------+---------------+-----+--------+---------+-----------+ 25 rows in set (0.00 sec)

将选择的标题改成中文

# 别名可以加as也可以不加 MariaDB [hellodb]> SELECT NAME as 姓名,AGE 年龄,stuid FROM students; +---------------+--------+-------+ | 姓名 | 年龄 | stuid | +---------------+--------+-------+ | Shi Zhongyu | 22 | 1 | | Shi Potian | 22 | 2 | | Xie Yanke | 53 | 3 | | Ding Dian | 32 | 4 | | Yu Yutong | 26 | 5 | | Shi Qing | 46 | 6 | | Xi Ren | 19 | 7 | | Lin Daiyu | 17 | 8 | | Ren Yingying | 20 | 9 | | Yue Lingshan | 19 | 10 | | Yuan Chengzhi | 23 | 11 | | Wen Qingqing | 19 | 12 | | Tian Boguang | 33 | 13 | | Lu Wushuang | 17 | 14 | | Duan Yu | 19 | 15 | | Xu Zhu | 21 | 16 | | Lin Chong | 25 | 17 | | Hua Rong | 23 | 18 | | Xue Baochai | 18 | 19 | | Diao Chan | 19 | 20 | | Huang Yueying | 22 | 21 | | Xiao Qiao | 20 | 22 | | Ma Chao | 23 | 23 | | Xu Xian | 27 | 24 | | Sun Dasheng | 100 | 25 | +---------------+--------+-------+ 25 rows in set (0.00 sec)

WHERE子句：指明过滤条件以实现“选择”的功能：

过滤条件：布尔型表达式算术操作符：+, -, *, /, % 比较操作符：=,<=>（相等或都为空）, <>, !=(非标准SQL), >, >=, <, <= BETWEEN min_num AND max_num IN (element1, element2, …) IS NULL IS NOT NULL

对特定行的操作WHERE

SQL注入

SELECT * FROM user WHERE usename='admin' and password='' or '1'='1'; SELECT * FROM user WHERE username='admin'--' and password=''';

DISTINCT 去除重复列

SELECT DISTINCT gender FROM students;

LIKE: % 任意长度的任意字符 _ 任意单个字符

RLIKE：正则表达式，索引失效，不建议使用

REGEXP：匹配字符串可用正则表达式书写模式，同上

逻辑操作符：

NOT AND OR XOR

GROUP：根据指定的条件把查询结果进行“分组”以用于做“聚合”运算

avg(), max(), min(), count(), sum()

HAVING: 对分组聚合运算后的结果指定过滤条件

ORDER BY: 根据指定的字段对查询结果进行排序

升序：ASC 降序：DESC

LIMIT [[offset,]row_count]：对查询的结果进行输出行数数量限制

对查询结果中的数据请求施加“锁”

FOR UPDATE: 写锁，独占或排它锁，只有一个读和写 LOCK IN SHARE MODE: 读锁，共享锁，同时多个读

检测某列是否为空

SELECT * FROM students WHERE classid IS null;

检测非空

SELECT * FROM students WHERE classid IS NOT null;

聚合函数

SELECT COUNT(ClassID) AS 记录行数 FROM students; /*返回非空的列对应的所有数量*/

如果要统计共有多少行，则直接选择主键，因为主键不能为空

MAX()

MIN()

平均年龄

MariaDB [hellodb]> SELECT AVG(age) AS 平均年龄 FROM students; +--------------+ | 平均年龄 | +--------------+ | 27.4000 | +--------------+

分组统计GROUP BY

SELECT ClassID , AVG(age) AS 平均年龄 FROM students GROUP BY ClassID;

一旦做了分组，SELECT 后的字段名必须是分组名与聚合函数

HAVING

分组之后再过滤

SELECT ClassID , AVG(age) AS 平均年龄 FROM students GROUP BY ClassID HAVING AVG(age) > 30;

注意：使用HAVING是在分组之后，而WHERE是在分组之前

加别名的写法

SELECT ClassID , AVG(age) AS avg FROM students GROUP BY ClassID HAVING avg > 30;

或

SELECT ClassID , AVG(age) AS 平均年龄 FROM students GROUP BY ClassID HAVING 平均年龄 > 30;

多次分组

MariaDB [hellodb]> SELECT classid,gender,AVG(age) FROM students GROUP BY classid,gender; +---------+--------+----------+ | classid | gender | AVG(age) | +---------+--------+----------+ | NULL | M | 63.5000 | | 1 | F | 19.5000 | | 1 | M | 21.5000 | | 2 | M | 36.0000 | | 3 | F | 18.3333 | | 3 | M | 26.0000 | | 4 | M | 24.7500 | | 5 | M | 46.0000 | | 6 | F | 20.0000 | | 6 | M | 23.0000 | | 7 | F | 18.0000 | | 7 | M | 23.0000 | +---------+--------+----------+ 12 rows in set (0.00 sec)

排序ORDER BY

默认是正序排

SELECT * FROM students ORDER BY age;

倒序排加DESC

SELECT * FROM students ORDER BY age DESC;

排除NULL至最后，只针对数字型有效：在搜索字段前加 -

SELECT * FROM students ORDER BY -classid DESC;

ORDER BY 与 GROUP BY的综合应用

按班级排序，显示每个班级年龄的总和

MariaDB [hellodb]> SELECT ClassID,SUM(age) AS age FROM students GROUP BY ClassID ORDER BY -classid DESC; +---------+------+ | ClassID | age | +---------+------+ | 1 | 82 | | 2 | 108 | | 3 | 81 | | 4 | 99 | | 5 | 46 | | 6 | 83 | | 7 | 59 | | NULL | 127 | +---------+------+ 8 rows in set (0.00 sec)

排除NULL值

MariaDB [hellodb]> SELECT ClassID,SUM(age) AS age FROM students GROUP BY ClassID HAVING classid IS NOT NULL ORDER BY -classid DESC; +---------+------+ | ClassID | age | +---------+------+ | 1 | 82 | | 2 | 108 | | 3 | 81 | | 4 | 99 | | 5 | 46 | | 6 | 83 | | 7 | 59 | +---------+------+ 7 rows in set (0.00 sec)

HAVING 关键字应当跟在GROUP BY之后

或者直接

MariaDB [hellodb]> SELECT ClassID,SUM(age) AS age FROM students WHERE ClassID IS NOT NULL GROUP BY ClassID ORDER BY -classid DESC; +---------+------+ | ClassID | age | +---------+------+ | 1 | 82 | | 2 | 108 | | 3 | 81 | | 4 | 99 | | 5 | 46 | | 6 | 83 | | 7 | 59 | +---------+------+ 7 rows in set (0.00 sec)

LIMIT

显示前几行数据

MariaDB [hellodb]> SELECT ClassID,SUM(age) AS age FROM students WHERE ClassID IS NOT NULL GROUP BY ClassID ORDER BY -classid DESC LIMIT 3; +---------+------+ | ClassID | age | +---------+------+ | 1 | 82 | | 2 | 108 | | 3 | 81 | +---------+------+ 3 rows in set (0.00 sec)

跳过前两行，取后续的3行

MariaDB [hellodb]> SELECT ClassID,SUM(age) AS age FROM students WHERE ClassID IS NOT NULL GROUP BY ClassID ORDER BY -classid DESC LIMIT 2,3; +---------+------+ | ClassID | age | +---------+------+ | 3 | 81 | | 4 | 99 | | 5 | 46 | +---------+------+ 3 rows in set (0.00 sec)

选择查看相应的ClassID信息

MariaDB [hellodb]> SELECT * FROM students WHERE ClassID in (1,3,5); +-------+--------------+-----+--------+---------+-----------+ | StuID | Name | Age | Gender | ClassID | TeacherID | +-------+--------------+-----+--------+---------+-----------+ | 2 | Shi Potian | 22 | M | 1 | 7 | | 5 | Yu Yutong | 26 | M | 3 | 1 | | 6 | Shi Qing | 46 | M | 5 | NULL | | 7 | Xi Ren | 19 | F | 3 | NULL | | 10 | Yue Lingshan | 19 | F | 3 | NULL | | 12 | Wen Qingqing | 19 | F | 1 | NULL | | 14 | Lu Wushuang | 17 | F | 3 | NULL | | 16 | Xu Zhu | 21 | M | 1 | NULL | | 22 | Xiao Qiao | 20 | F | 1 | NULL | +-------+--------------+-----+--------+---------+-----------+ 9 rows in set (0.00 sec)

练习

导入hellodb.sql生成数据库

[root@localhost ~]# mysql < hellodb_innodb.sql

(1) 在students表中，查询年龄大于25岁，且为男性的同学的名字和年龄

SELECT name,age FROM students WHERE age > 25 and Gender = 'M';

(2) 以ClassID为分组依据，显示每组的平均年龄

MariaDB [hellodb]> SELECT ClassID , AVG(age) AS 平均年龄 FROM students GROUP BY ClassID; +---------+--------------+ | ClassID | 平均年龄 | +---------+--------------+ | NULL | 63.5000 | | 1 | 20.5000 | | 2 | 36.0000 | | 3 | 20.2500 | | 4 | 24.7500 | | 5 | 46.0000 | | 6 | 20.7500 | | 7 | 19.6667 | +---------+--------------+ 8 rows in set (0.00 sec)

(3) 显示第2题中平均年龄大于30的分组及平均年龄

MariaDB [hellodb]> SELECT ClassID , AVG(age) AS 平均年龄 FROM students GROUP BY ClassID HAVING AVG(age) > 30; +---------+--------------+ | ClassID | 平均年龄 | +---------+--------------+ | NULL | 63.5000 | | 2 | 36.0000 | | 5 | 46.0000 | +---------+--------------+ 3 rows in set (0.00 sec)

(4) 显示以L开头的名字的同学的信息

MariaDB [hellodb]> SELECT * FROM students WHERE Name LIKE 'L%'; +-------+-------------+-----+--------+---------+-----------+ | StuID | Name | Age | Gender | ClassID | TeacherID | +-------+-------------+-----+--------+---------+-----------+ | 8 | Lin Daiyu | 17 | F | 7 | NULL | | 14 | Lu Wushuang | 17 | F | 3 | NULL | | 17 | Lin Chong | 25 | M | 4 | NULL | +-------+-------------+-----+--------+---------+-----------+ 3 rows in set (0.00 sec)

DQL多表查询与视图

两张表的纵向合并： UNION

最好是拥有相同的列的字段

MariaDB [hellodb]> SELECT StuID,Name,Age,Gender FROM students UNION SELECT * FROM teachers; +-------+---------------+-----+--------+ | StuID | Name | Age | Gender | +-------+---------------+-----+--------+ | 1 | Shi Zhongyu | 22 | M | | 2 | Shi Potian | 22 | M | | 3 | Xie Yanke | 53 | M | | 4 | Ding Dian | 32 | M | | 5 | Yu Yutong | 26 | M | | 6 | Shi Qing | 46 | M | | 7 | Xi Ren | 19 | F | | 8 | Lin Daiyu | 17 | F | | 9 | Ren Yingying | 20 | F | | 10 | Yue Lingshan | 19 | F | | 11 | Yuan Chengzhi | 23 | M | | 12 | Wen Qingqing | 19 | F | | 13 | Tian Boguang | 33 | M | | 14 | Lu Wushuang | 17 | F | | 15 | Duan Yu | 19 | M | | 16 | Xu Zhu | 21 | M | | 17 | Lin Chong | 25 | M | | 18 | Hua Rong | 23 | M | | 19 | Xue Baochai | 18 | F | | 20 | Diao Chan | 19 | F | | 21 | Huang Yueying | 22 | F | | 22 | Xiao Qiao | 20 | F | | 23 | Ma Chao | 23 | M | | 24 | Xu Xian | 27 | M | | 25 | Sun Dasheng | 100 | M | | 1 | Song Jiang | 45 | M | | 2 | Zhang Sanfeng | 94 | M | | 3 | Miejue Shitai | 77 | F | | 4 | Lin Chaoying | 93 | F | +-------+---------------+-----+--------+ 29 rows in set (0.00 sec)

UNION去重(默认)

SELECT * FROM students UNION SELECT * FROM students;

UNION ALL 不去重

DISTINCT去重

SELECT DISTINCT * FROM students;

横向合并

bash中的横向合并paste A B

[root@localhost ~]# seq 10 > f1 [root@localhost ~]# seq 10 20 > f2 [root@localhost ~]# paste f1 f2 1 10 2 11 3 12 4 13 5 14 6 15 7 16 8 17 9 18 10 19 20 # 在paste合并中，是f1文件的第1..n行与f2文件的1..n行合并

交叉连接

第一张表的每一行都与第二章表的全部行合并组合一次

这种合并叫做交叉连接,又称为笛卡尔合并，在数据库中叫CROSS JOIN

SELECT * FROM students CROSS JOIN SELECT * FROM teachers;

多表的内连接INNER JOIN(交集)

MariaDB [hellodb]> SELECT * FROM students INNER JOIN teachers ON students.teacherid=teachers.tid; +-------+-------------+-----+--------+---------+-----------+-----+---------------+-----+--------+ | StuID | Name | Age | Gender | ClassID | TeacherID | TID | Name | Age | Gender | +-------+-------------+-----+--------+---------+-----------+-----+---------------+-----+--------+ | 5 | Yu Yutong | 26 | M | 3 | 1 | 1 | Song Jiang | 45 | M | | 1 | Shi Zhongyu | 22 | M | 2 | 3 | 3 | Miejue Shitai | 77 | F | | 4 | Ding Dian | 32 | M | 4 | 4 | 4 | Lin Chaoying | 93 | F | +-------+-------------+-----+--------+---------+-----------+-----+---------------+-----+--------+

注意：如果定了别名，就一点得使用别名

# 老式写法 MariaDB [hellodb]> SELECT s.stuid, s.name , s.age,t.tid,t.name,t.age FROM students s ,teachers t where s.teacherid = t.tid; +-------+-------------+-----+-----+---------------+-----+ | stuid | name | age | tid | name | age | +-------+-------------+-----+-----+---------------+-----+ | 5 | Yu Yutong | 26 | 1 | Song Jiang | 45 | | 1 | Shi Zhongyu | 22 | 3 | Miejue Shitai | 77 | | 4 | Ding Dian | 32 | 4 | Lin Chaoying | 93 | +-------+-------------+-----+-----+---------------+-----+ 3 rows in set (0.00 sec)

ORM生成SQL语句

外连接

左外连接 LEFT OUTER JOIN

左边表的内容全要，而右边表只要交集

SELECT * FROM students LEFT OUTER JOIN teachers ON students.teacherid=teachers.tid;

没有对应关系的则显示NULL

右外连接 RIGHT OUTER JOIN

右边表内容全要，而左边的只要交集

SELECT * FROM students RIGHT OUTER JOIN teachers ON students.teacherid=teachers.tid;

在连表之后继续筛选 AND

SELECT * FROM students INNER JOIN teachers ON students.teacherid=teachers.tid AND students.age > 30;

完全外连接(并集)

默认mysql不支持全外连接，但是可以通过UNION将左外连接与右外连接合并

SELECT * FROM students LEFT OUTER JOIN teachers ON students.teacherid=teachers.tid UNION SELECT * FROM students RIGHT OUTER JOIN teachers ON students.teacherid=teachers.tid;

完全外连接后排除交集的部分

SELECT * FROM students LEFT OUTER JOIN teachers ON students.teacherid=teachers.tid UNION SELECT * FROM students RIGHT OUTER JOIN teachers ON students.teacherid=teachers.tid WHERE students.teacherid=teachers.tid IS NULL OR students.teacherid=teachers.tid IS NULL;

子查询

SELECT 嵌入于另一个SELECT语句中

查询年龄大于班级平均年龄的名单

MariaDB [hellodb]> SELECT * FROM students WHERE age > (SELECT AVG(age) FROM students); +-------+--------------+-----+--------+---------+-----------+ | StuID | Name | Age | Gender | ClassID | TeacherID | +-------+--------------+-----+--------+---------+-----------+ | 3 | Xie Yanke | 53 | M | 2 | 16 | | 4 | Ding Dian | 32 | M | 4 | 4 | | 6 | Shi Qing | 46 | M | 5 | NULL | | 13 | Tian Boguang | 33 | M | 2 | NULL | | 25 | Sun Dasheng | 100 | M | NULL | NULL | +-------+--------------+-----+--------+---------+-----------+ 5 rows in set (0.00 sec) UPDATE students SET age=(SELECT AVG(age) FROM teachers) WHERE stuid=25;

自连接

将一张表想象成两张表来自己连接自己(以取不同别名的形式)

SELECT e.name ,l.name FROM emp AS e INNER JOIN emp AS l ON e.leaderid=l.id

多表查询

先关联起两张表，再关联第三张表

MariaDB [hellodb]> SELECT * FROM scores; +----+-------+----------+-------+ | ID | StuID | CourseID | Score | +----+-------+----------+-------+ | 1 | 1 | 2 | 77 | | 2 | 1 | 6 | 93 | | 3 | 2 | 2 | 47 | | 4 | 2 | 5 | 97 | | 5 | 3 | 2 | 88 | | 6 | 3 | 6 | 75 | | 7 | 4 | 5 | 71 | | 8 | 4 | 2 | 89 | | 9 | 5 | 1 | 39 | | 10 | 5 | 7 | 63 | | 11 | 6 | 1 | 96 | | 12 | 7 | 1 | 86 | | 13 | 7 | 7 | 83 | | 14 | 8 | 4 | 57 | | 15 | 8 | 3 | 93 | +----+-------+----------+-------+ 15 rows in set (0.00 sec)

将students 表与scores表连接

MariaDB [hellodb]> SELECT st.name,sc.courseid,sc.score FROM students AS st INNER JOIN scores AS sc ON st.stuid=sc.stuid; +-------------+----------+-------+ | name | courseid | score | +-------------+----------+-------+ | Shi Zhongyu | 2 | 77 | | Shi Zhongyu | 6 | 93 | | Shi Potian | 2 | 47 | | Shi Potian | 5 | 97 | | Xie Yanke | 2 | 88 | | Xie Yanke | 6 | 75 | | Ding Dian | 5 | 71 | | Ding Dian | 2 | 89 | | Yu Yutong | 1 | 39 | | Yu Yutong | 7 | 63 | | Shi Qing | 1 | 96 | | Xi Ren | 1 | 86 | | Xi Ren | 7 | 83 | | Lin Daiyu | 4 | 57 | | Lin Daiyu | 3 | 93 | +-------------+----------+-------+ 15 rows in set (0.00 sec)

在将此表格与course表连接

视图:虚拟表

将一个复杂的语句，转变为一个视图，影藏了数据库的复杂性，类似于一张虚拟表

创建VIEW

CREAT VIEW VIEW_NAME

将上文中查询的表格定义成一个VIEW

检查一张表是否为视图

MariaDB [hellodb]> show table status like 'view_test'\G *************************** 1. row *************************** Name: view_test Engine: NULL Version: NULL Row_format: NULL Rows: NULL Avg_row_length: NULL Data_length: NULL Max_data_length: NULL Index_length: NULL Data_free: NULL Auto_increment: NULL Create_time: NULL Update_time: NULL Check_time: NULL Collation: NULL Checksum: NULL Create_options: NULL Comment: VIEW # 显示为一个视图 1 row in set (0.01 sec)

视图现在已经不建议使用

删除视图

函数存储过程、触发器及用户管理

函数

Function and Operator Reference

系统自带函数

自定义函数

保存在mysql.proc表中创建UDF CREATE [AGGREGATE] FUNCTION function_name(parameter_name type,[parameter_name type,...]) RETURNS {STRING|INTEGER|REAL} runtime_body

说明：

参数可以有多个,也可以没有参数必须有且只有一个返回值,不能返回多个值

创建函数

创建一个简单的无参数函数

CREATE FUNCTION simpleFun() RETURNS VARCHAR(20) RETURN "Hello World!";

使用函数是必须嵌入在SELECT语句中

SELECT simpleFun(); MariaDB [hellodb]> SELECT simpleFun(); +--------------+ | simpleFun() | +--------------+ | Hello World! | +--------------+ 1 row in set (0.00 sec)

查看函数列表

SHOW FUNCTION STATUS # 竖着显示 MariaDB [hellodb]> SHOW FUNCTION STATUS \G *************************** 1. row *************************** Db: hellodb Name: simpleFun Type: FUNCTION Definer: root@localhost Modified: 2020-06-29 14:15:16 Created: 2020-06-29 14:15:16 Security_type: DEFINER Comment: character_set_client: utf8 collation_connection: utf8_general_ci Database Collation: utf8_general_ci 1 row in set (0.00 sec)

查看函数定义

SHOW CREATE FUNCTION function_name MariaDB [hellodb]> SHOW CREATE FUNCTION simpleFun \G *************************** 1. row *************************** Function: simpleFun sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION Create Function: CREATE DEFINER=`root`@`localhost` FUNCTION `simpleFun`() RETURNS varchar(20) CHARSET utf8 RETURN "Hello World!" character_set_client: utf8 collation_connection: utf8_general_ci Database Collation: utf8_general_ci 1 row in set (0.00 sec)

或者直接查看mysql.proc

MariaDB [hellodb]> SELECT * FROM mysql.proc \G *************************** 1. row *************************** db: mysql name: AddGeometryColumn type: PROCEDURE specific_name: AddGeometryColumn language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: INVOKER param_list: catalog varchar(64), t_schema varchar(64), t_name varchar(64), geometry_column varchar(64), t_srid int returns: body: begin set @qwe= concat('ALTER TABLE ', t_schema, '.', t_name, ' ADD ', geometry_column,' GEOMETRY REF_SYSTEM_ID=', t_srid); PREPARE ls from @qwe; execute ls; deallocate prepare ls; end definer: root@localhost created: 2020-06-26 21:10:47 modified: 2020-06-26 21:10:47 sql_mode: comment: character_set_client: utf8 collation_connection: utf8_general_ci db_collation: latin1_swedish_ci body_utf8: begin set @qwe= concat('ALTER TABLE ', t_schema, '.', t_name, ' ADD ', geometry_column,' GEOMETRY REF_SYSTEM_ID=', t_srid); PREPARE ls from @qwe; execute ls; deallocate prepare ls; end *************************** 2. row *************************** db: mysql name: DropGeometryColumn type: PROCEDURE specific_name: DropGeometryColumn language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: INVOKER param_list: catalog varchar(64), t_schema varchar(64), t_name varchar(64), geometry_column varchar(64) returns: body: begin set @qwe= concat('ALTER TABLE ', t_schema, '.', t_name, ' DROP ', geometry_column); PREPARE ls from @qwe; execute ls; deallocate prepare ls; end definer: root@localhost created: 2020-06-26 21:10:47 modified: 2020-06-26 21:10:47 sql_mode: comment: character_set_client: utf8 collation_connection: utf8_general_ci db_collation: latin1_swedish_ci body_utf8: begin set @qwe= concat('ALTER TABLE ', t_schema, '.', t_name, ' DROP ', geometry_column); PREPARE ls from @qwe; execute ls; deallocate prepare ls; end *************************** 3. row *************************** db: hellodb name: simpleFun type: FUNCTION specific_name: simpleFun language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: DEFINER param_list: returns: varchar(20) CHARSET utf8 body: RETURN "Hello World!" definer: root@localhost created: 2020-06-29 14:15:16 modified: 2020-06-29 14:15:16 sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION comment: character_set_client: utf8 collation_connection: utf8_general_ci db_collation: utf8_general_ci body_utf8: RETURN "Hello World!" 3 rows in set (0.00 sec)

删除UDF

DROP FUNCTION function_name

自定义函数

DELIMITER // CREATE FUNCTION deleteById(uid SMALLINT UNSIGNED) RETURNS VARCHAR(20) BEGIN DELETE FROM students WHERE stuid = uid; RETURN (SELECT COUNT(stuid) FROM students); END// DELIMITER ; MariaDB [hellodb]> DELIMITER // MariaDB [hellodb]> CREATE FUNCTION deleteById(uid SMALLINT UNSIGNED) RETURNS VARCHAR(20) -> BEGIN -> DELETE FROM students WHERE stuid = uid; -> RETURN (SELECT COUNT(stuid) FROM students); -> END// Query OK, 0 rows affected (0.00 sec) MariaDB [hellodb]> DELIMITER ;

定义函数内部变量DECLARE 变量1[,变量2,... ]变量类型 [DEFAULT 默认值]

DELIMITER // CREATE FUNCTION addTwoNumber(x SMALLINT UNSIGNED, Y SMALLINT UNSIGNED) RETURNS SMALLINT BEGIN DECLARE a, b SMALLINT UNSIGNED; SET a = x, b = y; RETURN a+b; END// DELIMITER ;

为变量赋值语法

SET parameter_name = value[,parameter_name = value...] SELECT INTO parameter_name

示例

DECLARE x int; SELECT COUNT(id) FROM tdb_name INTO x; RETURN x; END//

调用自定义函数语法

SELECT function_name(parameter_value,...) MariaDB [hellodb]> SELECT deleteById(10); +----------------+ | deleteById(10) | +----------------+ | 24 | +----------------+ 1 row in set (0.01 sec)

存储过程

存储过程优势

存储过程把经常使用的SQL语句或业务逻辑封装起来,预编译保存在数据库中,当需要时从数据库中直接调用,省去了编译的过程提高了运行速度同时降低网络数据传输量

存储过程与自定义函数的区别

存储过程实现的过程要复杂一些,而函数的针对性较强存储过程可以有多个返回值,而自定义函数只有一个返回值存储过程一般可独立执行,而函数往往是作为其他SQL语句的一部分来使用

创建存储过程

CREATE PROCEDURE sp_name ([ proc_parameter [,proc_parameter ...]]) routime_body proc_parameter : [IN|OUT|INOUT] parameter_name type # 其中IN表示输入参数，OUT表示输出参数，INOUT表示既可以输入也可以输出；param_name表示参数名称；type表示参数的类型

创建无参存储过程

delimiter // CREATE PROCEDURE showTime() BEGIN SELECT now(); END// delimiter ; CALL showTime;

调用

MariaDB [hellodb]> delimiter // MariaDB [hellodb]> CREATE PROCEDURE showTime() -> BEGIN -> SELECT now(); -> END// Query OK, 0 rows affected (0.00 sec) MariaDB [hellodb]> delimiter ; ############################################################## MariaDB [hellodb]> CALL showTime; +---------------------+ | now() | +---------------------+ | 2020-06-29 14:40:46 | +---------------------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec)

创建含参存储过程：只有一个IN参数

delimiter // CREATE PROCEDURE selectById(IN uid SMALLINT UNSIGNED) BEGIN SELECT * FROM students WHERE stuid = uid; END// delimiter ; ########################################## call selectById(2);

全局变量@

delimiter // CREATE PROCEDURE dorepeat(n INT) BEGIN SET @i = 0; SET @sum = 0; REPEAT SET @sum = @sum+@i; SET @i = @i + 1; UNTIL @i > n END REPEAT; END// delimiter ; CALL dorepeat(100); SELECT @sum; # @sum = 5050 # @i = 101

创建含参存储过程:包含IN参数和OUT参数

delimiter // CREATE PROCEDURE deleteById(IN uid SMALLINT UNSIGNED, OUT num SMALLINT UNSIGNED) BEGIN DELETE FROM students WHERE stuid >= uid; SELECT row_count() into num; END// delimiter ; call deleteById(2,@Line); SELECT @Line;

说明:创建存储过程deleteById,包含一个IN参数和一个OUT参数.调用时,传入删除的ID和保存被修改的行数值的用户变量@Line,select @Line;输出被影响行数

查看存储过程列表

SHOW PROCEDURE STATUS;

查看存储过程定义

SHOW CREATE PROCEDURE sp_name

调用存储过程CALL

CALL sp_name ([ proc_parameter [,proc_parameter ...]]) CALL sp_name #说明:当无参时,可以省略"()",当有参数时,不可省略"()”

存储过程修改

ALTER语句修改存储过程只能修改存储过程的注释等无关紧要的东西,不能修改存储过程体,所以要修改存储过程,方法就是删除重建

删除存储过程

DROP PROCEDURE [IF EXISTS] sp_name

流程控制

存储过程和函数中可以使用流程控制来控制语句的执行流程控制：

IF：用来进行条件判断。根据是否满足条件，执行不同语句CASE：用来进行条件判断，可实现比IF语句更复杂的条件判断LOOP：重复执行特定的语句，实现一个简单的循环LEAVE：用于跳出循环控制ITERATE：跳出本次循环，然后直接进入下一次循环REPEAT：有条件控制的循环语句。当满足特定条件时，就会跳出循环语句WHILE：有条件控制的循环语句

触发器

触发器的执行不是由程序调用，也不是由手工启动，而是由事件来触发、激活从而实现执行

创建触发器

CREATE [DEFINER = { user | CURRENT_USER }] TRIGGER trigger_name trigger_time trigger_event ON tbl_name FOR EACH ROW trigger_body ###说明### trigger_name：触发器的名称 trigger_time：{ BEFORE | AFTER }，表示在事件之前或之后触发 trigger_event:：{ INSERT |UPDATE | DELETE }，触发的具体事件 tbl_name：该触发器作用在表名

触发器示例

CREATE TABLE student_info ( stu_id INT(11) NOT NULL AUTO_INCREMENT, stu_name VARCHAR(255) DEFAULT NULL, PRIMARY KEY (stu_id) ); CREATE TABLE student_count ( student_count INT(11) DEFAULT 0 ); INSERT INTO student_count VALUES(0);

示例：创建触发器，在向学生表INSERT数据时，学生数增加，DELETE学生时，学生数减少

CREATE TRIGGER trigger_student_count_insert AFTER INSERT ON student_info FOR EACH ROW UPDATE student_count SET student_count=student_count+1; CREATE TRIGGER trigger_student_count_delete AFTER DELETE ON student_info FOR EACH ROW UPDATE student_count SET student_count=student_count-1;

查看触发器

SHOW TRIGGERS

查询系统表information_schema.triggers的方式指定查询条件，查看指定的触发器信息

USE information_schema; Database changed SELECT * FROM triggers WHERE trigger_name='trigger_student_count_insert';

删除触发器

DROP TRIGGER trigger_name;

MYSQL用户和权限管理

元数据数据库：mysql 系统授权表：

db, host, usercolumns_priv, tables_priv, procs_priv, proxies_priv

用户账号：

‘USERNAME’@‘HOST’ @‘HOST’: 主机名 IP地址或Network 通配符： % _ 示例：172.16.%.%

用户账户位置

注意其他版本账户管理信息可能会放在authentication_string列中

创建用户

CREATE USER 'USERNAME'@'HOST' [IDENTIFIED BY 'password']；

默认权限：USAGE

用户重命名RENAME USER

RENAME USER old_user_name TO new_user_name;

删除用户

DROP USER 'USERNAME'@'HOST‘

示例：删除默认的空用户

DROP USER ''@'localhost';

修改密码

SET PASSWORD FOR 'user'@'host' = PASSWORD(‘password');

有时候mysql会自动将127.0.0.1反向解析成localhost

因此我们关闭反向解析的操作的变量为skip_name_resolve

[root@localhost ~]# vim /etc/my.cnf [musqld] skip_name_resolve ####重启服务##### systemctl restart mariadb

用UPDATE命令直接更改数据库表

UPDATE mysql.user SET password=PASSWORD('password') WHERE clause; # 此方法需要执行下面指令才能生效： FLUSH PRIVILEGES;

破解口令方法

在配置文件中加入skip_grant_tables与skip_networking,再重新启动

为了数据库的安全，必须加入跳过远程登录选项！

MYSQL架构和存储引擎详解

MYSQL权限类别

管理类

CREATE TEMPORARY TABLES CREATE USER FILE SUPER SHOW DATABASES RELOAD SHUTDOWN REPLICATION SLAVE REPLICATION CLIENT LOCK TABLES PROCESS

程序类

FUNCTION、PROCEDURE、TRIGGER CREATE ALTER DROP EXCUTE

库和表级别

DATABASE、TABLE ALTER CREATE CREATE VIEW DROP INDEX SHOW VIEW GRANT OPTION # 能将自己获得的权限转赠给其他用户

数据操作

SELECT INSERT DELETE UPDATE

字段级别

SELECT(col1,col2,...) UPDATE(col1,col2,...) INSERT(col1,col2,...)

所有权限

ALL PRIVILEGES 或 ALL

授权

GRANT priv_type [(column_list)],... ON [object_type] priv_level TO 'user'@'host' [IDENTIFIED BY 'password'] [WITH GRANT OPTION]; # priv_type: ALL [PRIVILEGES] # object_type:TABLE | FUNCTION | PROCEDURE # priv_level: *(所有库) | *.* | db_name.* | db_name.tbl_name | tbl_name(当前库的表) | db_name.routine_name(指定库的函数,存储过程,触发器) with_option: GRANT OPTION # 赋予他人授权权限 | MAX_QUERIES_PER_HOUR count | MAX_UPDATES_PER_HOUR count | MAX_CONNECTIONS_PER_HOUR count | MAX_USER_CONNECTIONS count # 示例：GRANT SELECT (col1), INSERT (col1,col2) ON mydb.mytbl TO 'someuser'@'somehost‘;

GRANT Statement

示例

查看授权用户信息

MariaDB [hellodb]> SHOW GRANTS FOR test@'192.168.37.%'\G; *************************** 1. row *************************** Grants for test@192.168.37.%: GRANT USAGE ON *.* TO 'test'@'192.168.37.%' IDENTIFIED BY PASSWORD '*128977E278358FF80A246B5046F51043A2B1FCED' *************************** 2. row *************************** Grants for test@192.168.37.%: GRANT ALL PRIVILEGES ON `hellodb`.* TO 'test'@'192.168.37.%' 2 rows in set (0.00 sec)

回收授权REVOKE

取消删除表格权利

REVOKE DELETE ON hellodb.* FROM test@'192.168.37.%'; MariaDB [hellodb]> SHOW GRANTS FOR test@'192.168.37.%' \G; *************************** 1. row *************************** Grants for test@192.168.37.%: GRANT USAGE ON *.* TO 'test'@'192.168.37.%' IDENTIFIED BY PASSWORD '*128977E278358FF80A246B5046F51043A2B1FCED' *************************** 2. row *************************** Grants for test@192.168.37.%: GRANT SELECT, INSERT, UPDATE, CREATE, DROP, REFERENCES, INDEX, ALTER, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, EVENT, TRIGGER ON `hellodb`.* TO 'test'@'192.168.37.%' # 取消DROP同理

查看当前用户权限

MariaDB [hellodb]> SHOW GRANTS FOR CURRENT_USER(); +---------------------------------------------------------------------+ | 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)

注意：MariaDB服务进程启动时会读取mysql库中所有授权表至内存 (1) GRANT或REVOKE等执行权限操作会保存于系统表中，MariaDB的服务进程通常会自动重读授权表，使之生效 (2) 对于不能够或不能及时重读授权表的命令，可手动让MariaDB的服务进程重读授权表：mysql> FLUSH PRIVILEGES;

练习

数据库授权magedu用户，允许192.168.1.0/24网段可以连接mysql

MariaDB [mysql]> CREATE USER magedu@'192.168.1.%' IDENTIFIED BY 'centos'; Query OK, 0 rows affected (0.00 sec)

检查用户表

MariaDB [mysql]> SELECT user,host,password from user; +--------+-----------------------+-------------------------------------------+ | user | host | password | +--------+-----------------------+-------------------------------------------+ | root | localhost | | | root | localhost.localdomain | | | root | 127.0.0.1 | | | root | ::1 | | | | localhost | | | | localhost.localdomain | | | magedu | 192.168.1.% | *128977E278358FF80A246B5046F51043A2B1FCED | +--------+-----------------------+-------------------------------------------+ 7 rows in set (0.00 sec) MariaDB [mysql]> SELECT * FROM user WHERE user='magedu' \G; *************************** 1. row *************************** Host: 192.168.1.% User: magedu Password: *128977E278358FF80A246B5046F51043A2B1FCED Select_priv: N Insert_priv: N Update_priv: N Delete_priv: N Create_priv: N Drop_priv: N Reload_priv: N Shutdown_priv: N Process_priv: N File_priv: N Grant_priv: N References_priv: N Index_priv: N Alter_priv: N Show_db_priv: N Super_priv: N Create_tmp_table_priv: N Lock_tables_priv: N Execute_priv: N Repl_slave_priv: N Repl_client_priv: N Create_view_priv: N Show_view_priv: N Create_routine_priv: N Alter_routine_priv: N Create_user_priv: N Event_priv: N Trigger_priv: N Create_tablespace_priv: N ssl_type: ssl_cipher: x509_issuer: x509_subject: max_questions: 0 max_updates: 0 max_connections: 0 max_user_connections: 0 plugin: authentication_string: password_expired: N is_role: N default_role: max_statement_time: 0.000000 1 row in set (0.00 sec) ERROR: No query specified

MYSQL架构

存储引擎

FeatureMyISAMMemoryInnoDBArchiveNDBB-tree indexesYesYesYesNoNoBackup/point-in-time recoveryYesYesYesYesYesCluster database supportNoNoNoNoYesClustered indexesNoNoYesNoNoCompressed dataYesNoYesYesNoData cachesNoN/AYesNoYesEncrypted dataYesYesYesYesYesForeign key supportNoNoYesNoYesFull-text search indexesYesNoYesNoNoGeospatial data type supportYesNoYesYesYesGeospatial indexing supportYesNoYesNoNoHash indexesNoYesNoNoYesIndex cachesYesN/AYesNoYesLocking granularityTableTableRowRowRowMVCCNoNoYesNoNoReplication supportYesLimitedYesYesYesStorage limits256TBRAM64TBNone384EBT-tree indexesNoNoNoNoYesTransactionsNoNoYesNoYesUpdate statistics for data dictionaryYesYesYesYesYes

Transactions 事务

特性：

原子性一个事务是由多个小的步骤组成，要么所有步骤都完成，要么什么也不做

MyISAM引擎特点

不支持事务表级锁定读写相互阻塞，写入不能读，读时不能写只缓存索引不支持外键约束不支持聚簇索引读取数据较快，占用资源较少不支持MVCC（多版本并发控制机制）高并发崩溃恢复性较差MySQL5.5.5前默认的数据库引擎

MyISAM存储引擎适用场景只读（或者写较少）、表较小（可以接受长时间进行修复操作）

MyISAM引擎文件

tbl_name.frm 表格式定义tbl_name.MYD 数据文件tbl_name.MYI 索引文件

InnoDB引擎特点

行级锁支持事务，适合处理大量短期事务读写阻塞与事务隔离级别相关可缓存数据和索引支持聚簇索引崩溃恢复性更好支持MVCC高并发从MySQL5.5后支持全文索引从MySQL5.5.5开始为默认的数据库引擎

InnoDB数据库文件

所有InnoDB表的数据和索引放置于同一个表空间中表空间文件：datadir定义的目录下数据文件：ibddata1, ibddata2, …每个表单独使用一个表空间存储表的数据和索引启用：innodb_file_per_table=ON 参看：https://mariadb.com/kb/en/library/xtradbinnodb-server-system-variables/#innodb_file_per_table ON (>= MariaDB 5.5)两类文件放在数据库独立目录中数据文件(存储数据和索引)：tb_name.ibd 表格式定义：tb_name.frm

其他存储引擎

Performance_Schema：Performance_Schema数据库使用

Memory ：将所有数据存储在RAM中，以便在需要快速查找参考和其他类似数据的环境中进行快速访问。适用存放临时数据。引擎以前被称为HEAP引擎

MRG_MyISAM：使MySQL DBA或开发人员能够对一系列相同的MyISAM表进行逻辑分组，并将它们作为一个对象引用。适用于VLDB(Very Large Data Base)环境，如数据仓库

Archive ：为存储和检索大量很少参考的存档或安全审核信息，只支持SELECT和INSERT操作；支持行级锁和专用缓存区

Federated联合：用于访问其它远程MySQL服务器一个代理，它通过创建一个到远程MySQL服务器的客户端连接，并将查询传输到远程服务器执行，而后完成数据存取，提供链接单独MySQL服务器的能力，以便从多个物理服务器创建一个逻辑数据库。非常适合分布式或数据集市环境

BDB：可替代InnoDB的事务引擎，支持COMMIT、ROLLBACK和其他事务特性

Cluster/NDB：MySQL的簇式数据库引擎，尤其适合于具有高性能查找要求的应用程序，这类查找需求还要求具有最高的正常工作时间和可用性

CSV：CSV存储引擎使用逗号分隔值格式将数据存储在文本文件中。可以使用CSV引擎以CSV格式导入和导出其他软件和应用程序之间的数据交换

BLACKHOLE ：黑洞存储引擎接受但不存储数据，检索总是返回一个空集。该功能可用于分布式数据库设计，数据自动复制，但不是本地存储

example：“stub”引擎，它什么都不做。可以使用此引擎创建表，但不能将数据存储在其中或从中检索。目的是作为例子来说明如何开始编写新的存储引擎

管理存储引擎

查看mysql支持的存储引擎

SHOW ENGINES \G;

查看当前默认的存储引擎

SHOW VARIABLES LIKE '%storage_engine%';

设置默认的存储引擎

vim /etc/my.conf [mysqld] default_storage_engine= InnoDB

查看库中所有表使用的存储引擎

SHOW TABLE STATUS FROM db_name;

查看库中指定表的存储引擎

SHOW TABLE STATUS LIKE 'tb_name'; SHOW CREATE TABLE tb_name;

设置表的存储引擎

CREATE TABLE tb_name(... ) ENGINE=InnoDB; ALTER TABLE tb_name ENGINE=InnoDB;

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