數據庫結構模型分類
1、層次模型
2、網狀模型
3、關係模型
關係模型的組成部分
二維關係
表
row
column
索引
index
視圖
view (只包含固定字段,不包含其他字段)
關係型數據庫的常見組件:
數據庫 : Database
表 : table
行 : row
列 : column
索引 : index
視圖 : view
用戶 : user
權限 : privilege
存儲過程 : procedure
存儲函數 : function
觸發器 : trigger
事件調度器 : event schedule
DBA的組成部分
SQL引擎
分析器
計劃執行器
優化器
操作求解器
存儲引擎
文件和存儲接口
緩衝管理器
磁盤空間管理器
恢復管理器
事務管理器
鎖管理器
SQL接口(structured query Language)
類似於OS的shell接口,操作數據庫的數據接口,也提供了編程功能
SQL接口語言的標準(其由ANSL組織定義)
SQL86
SQL89
SQL92
SQL99
SQL03
SQL接口的語言分類
DDL:(Data Defined Language)
create
alter
drop
DML:(Data Manapulating Language)
insert
delete
update
select
DCL: (Data Control Language)
grant
revoke
DB是否支持事務的測試標準
ACID
A : 原子性 --> 不可分割的整體
C : 一致性 --> 數據的變化是一致性的
I : 隔離性 --> 事務彼此之間是隔離的
D : 持久性 --> 只要一個事務完成,它都是持久完成的。
事務是將組織多個操作爲一個整體,要麼全部執行,要全部不執行。其實現機制爲:
回滾機制
事務機制
RDBMS設計範式基礎概念
設計關係數據庫時,遵從不同的規範要求,設計出合理的關係型數據庫,這些不同的規範要求被稱爲不同的範式,各種範式呈遞次規範,越高的範式數據庫冗餘越小。目前關係數據庫有六種範式:第一範式(1NF)、第二範式(2NF)、第三範式(3NF)、巴德斯科範式(BCNF)、第四範式(4NF)和第五範式(5NF,又稱完美範式)。滿足最低要求的範式是第一範式(1NF)。在第一範式的基礎上進一步滿足更多規範要求的稱爲第二範式(2NF),其餘範式以次類推。一般說來,數據庫只需滿足第三範式(3NF)就行了。
1) 第一範式(1NF)
所謂第一範式(1NF)是指在關係模型中,對域添加的一個規範要求,所有的域都應該是原子性的,即數據庫表的每一列都是不可分割的原子數據項,而不能是集合,數組,記錄等非原子數據項。即實體中的某個屬性有多個值時,必須拆分爲不同的屬性。在符合第一範式(1NF)表中的每個域值只能是實體的一個屬性或一個屬性的一部分。簡而言之,第一範式就是無重複的域,並不可分析
2) 第二範式 (2NF)
第二範式(2NF)是在第一範式(1NF)的基礎上建立起來的,即滿足第二範式(2NF)必須先滿足第一範式(1NF)。第二範式(2NF)要求數據庫表中的每個實例或記錄必須可以被唯一地區分,即不能有兩個行是一樣的。選取一個能區分每個實體的屬性或屬性組,作爲實體的唯一標識。
3) 第三範式 (3NF)
第三範式(3NF)是第二範式(2NF)的一個子集,即滿足第三範式(3NF)必須滿足第二範式(2NF)。簡而言之,第三範式(3NF)要求一個關係中不包含已在其它關係已包含的非主關鍵字信息。簡而言之,不依賴於非主屬性,表與子表中不能有相同的字段。
數據庫的運行模型:
數據庫爲C/S架構,如下:
S : server ,監聽於套接字止,接收並處理客戶端的應用請求
C : Client
程序接口
CLI
GUI
應用編程接口
ODBC : Open Database Connection(開放式數據互聯)
MYSQL的工作模型
單進程多線程
用戶連接通過線程實現
一個線程池可以定義mysql的併發連接
處理用戶連接的叫連接線程
數據字典:數據一切的元數據信息,依賴mysql庫來存儲
數據庫的基礎概念
1)約束 : Constraint
主鍵 : 一個或多個字段的組合,填入的數據必須能在本表中唯一標識本行,且必須提供數據,即NOT NULL
唯一鍵 : 一個或多個字段的組合,填入的數據必須能在本表中唯一標識本行,允許爲null
外鍵 : 一個表中的某字段可填入數據取決於另一個表中的主鍵已有的數據。
檢查性約束 : 表達式約束,取決於表達式的要求
2) 索引 : 將表中的一個或多個字段中的數據複製一份另存,並且這些字段需要按特定的次序排序存儲,常見的索引類型:
樹形索引(MariaDB默認爲Btree索引)
bash索引索引有利於讀請求,但不得寫請求
3) 關係運算
選擇 : 挑選出符合條件的行(部分)
投影 : 挑選出需要的字段
連接 : 將多張表關聯起來
內連接
外連接
左外連接
右外連接
自連接
4)數據抽象 :
物理層 : 決定數據的存儲格式,即RDBMS 在磁盤上如何組織文件
邏輯層 : 描述DB存儲什麼數據,以及數據間存在什麼樣的關係
視圖層 : 描述DB中的部分數據
5) 關係模型的分類
關係模型
實體關係模型
基於對象的關係模型
半結構化的關係模型
XML格式就是一種半結構化數據
常見的RDBMS數據庫
MySQL
MariaDB
PostgreSQL(pgsql)
Oracle
MSSQL
=============
MariaDB的特性
插件式存儲引擎(注:存儲引擎也稱之爲"表類型")
MYISAM --> Aria
不支持事務
INNODB --> XtraDB
支持事務
諸多擴展和新特性
提供了更多的測試組件
truly open source
Mariadb的安裝
通用二進制格式安裝過程
a. 準備數據目錄
以/mydata/data爲例;
b. 配置mariadb
# groupadd -r -g 306 mysql
# useradd -r -g 306 -u 306 mysql
# tar xf mariadb-VERSION.tar.xz -C /usr/local
# ln -sv mariadb-version mysql
# cd /usr/local/mysql
# chown -R root:mysql ./*
# scripts/mysql_install_db --datadir=/mydata/data --user=mysql
# cp supper-files/mysql.server /etc/rc.d/init.d/mysqld
# chkconfig --add mysqld
c. 準備配置文件
配置格式:類ini格式,爲各程序均通過單個配置文件提供配置信息;
[prog_name]
能用二進制格式安裝,配置文件查找次序:
/etc/my.cnf --> /etc/mysql/my.cnf --> --default-extra-file=/PATH/TO/CONF_FILE --> ~/.my.cnf
OS提供的mariadb rpm包安裝的配置文件查找次序:
/etc/mysql/my.cnf --> /etc/my.cnf --> --default-extra=/PATH/TO/conf_file --> ~/my.cnf
以上兩者越靠後就是最後生效的.
# mkdir /etc/mysql
# cp support-files/my-large.cnf /etc/mysql/my.cnf
添加三個選項:
[mysqld]
datadir = /mydata/data
innodb_file_per_table = on
skip_name_resolve = on
MariDB程序的組成
Client
mysql : CLI交互式客戶端程序
mysqldump : 備份工具
mysqladmin: 管理工具
mysqlbinlog : 查看二進制日誌工具
Server
mysqld: 服務端進程
mysqld_safe : 服務端進程,默認也是運行的此進程
mysqld_multi : 服務端進程, 多實例
mysql_upgrade : 升級工具
服務端監聽的兩種socket地址
ip socket
監聽在3306/tcp,支持遠程通信
unix socket
監聽在sock文件上(/tmp/mysql.sock, /var/lib/mysql/mysql.sock),僅支持本地通信,通信主機爲localhost,127.0.0.1都基於unix socket文件通信
命令行交互式客戶端程序---mysql工具
options
-uUSERNAME : 用戶名,默認爲root
-hHOST : 服務器主機,默認爲localhost
-pPASSWD : 用戶的密碼
dDB_NAME: 連接到服務端之後,指明默認數據庫
-e 'SCRIPT' : 連接至MYSQL運行某命令後,直接退出,並返回結果````mysql -uroot -h127.0.0.1 -pmagedu -e 'show databases;'
注意: mysql的用戶帳號由兩部分組成,'username'@'hostname',其中host用於限制此用戶可通過哪些主機連接當前的MSYQL服務器
支持通配符:
% : 匹配任意長度的任意字符
172.16.%.%
_ : 匹配任意單個字符
內置命令
\u DB_NAME : 設定哪個庫爲默認數據庫
\q : 退出
\d CHAR : 設定新的語句結束符
\g : 語句通用結束標記
\G : 語句結束標記,但以豎排方式顯示
\s : 返回客戶端與服務端的連接狀態
\c : 取消命令運行
通過mysql協議發往服務器執行並取回結果,每個命令都必須有結束符,默認爲";",示例如下:
for i in {1..100};do AGE=$[$RANDOM%100];mysql -uroot -pM8T9cw -e "insert mydb.student(id,name,age) value ($i,\"stu$i\",$AGE);"; done
獲取命令幫助
help
SQL中的數據類型
字符型
定長字符型 : (最多255個字符)
CHAR(#) : 不區分字符大小寫
BINARY(#) : 區分字符大小寫
可變長字符型 :
VARCHAR(#) : 不區分字符大小寫,需要在字符長度加1,最多65536個字符
VARBINARY(#) : 區分字符大小寫,需要在字符長度加1,最多65536個字符
TEXT : 可存文本(2^32)個字符,只能存純文本,不區分大小寫
TINYTEXT
TEXT
MEDIUMTEXT
LONGTEXT
BLOB : 文本(2^32)個字符,可以存儲圖片
內置類型
SET : 集合
ENUM : 枚舉
數值型
精確數值型
INT
TINYINT : 一個字節
SMALLINT : 二個字節
MEDINUMINT : 三個字節
INT : 四個字節
BIGINT : 八個字節
近似數據型
FLOAT : 單精度
DOBULE : 雙精度
日期時間型
DATE : 日期型
TIME : 時間型
DATETIME : 日期時間型
TIMESTAMP : 時間戳(從過去到現在經過的秒數)
YEAR(2) : 2位年數
YEAR(4) : 4位年數
數據類型修飾符
所有類型都適用:
NOT NULL : 非空
DEFAULT value : 默認值
數值型適用
AUTO_INCREMENT : 自增長
UNSIGNED : 無符號,通常用於Int後面,進行修飾爲正整數
字段修飾符
PRIMARY KEY : 主鍵定義
UNIQUE KEY : 唯一鍵定義
==========
數據庫操作語言
數據庫操作
使用格式
create database | schema [if not exists]'DB_NAME';
drop database | schema 'DB_NAME';
查看數據庫
show databases;
創建數據庫
create database mydb;
刪除數據庫
drop database mydb;
查看支持的所有字符集
show character set;
查看支持的所有排序規則
show collation;
修改數據庫的默認字符集
alter database testdb character set utf32;
修改數據庫的默認字符排序規則
alter database testdb collate utf32_sinhala_ci;
表操作
使用格式
create table [if not exists] tb_name (col1 datatype 修飾符, col2 datatype 修飾符) engine=' '
查看所有的引擎(被支持的)
show engines
查看所有數據庫中的表
show tables;
show tables from mysql;
查看錶結構
desc students;
創建表
create table students(id int unsigned not null primary key, name varchar(30) not null, age tinyint unsigned not null,gender enum('F','M'))
向表中添加字段
alter table students add second_name char(30);
向表中刪除字段
alter table students drop second_name;
對錶添加主鍵
alter table students2 add primary key (id);
對錶刪除主鍵
alter table students2 drop primary key;
對錶添加索引
alter table students2 add index name (name);
對錶刪除索引
alter table students2 drop index name;
drop index name on students2;
對錶添加唯一鍵
alter table students drop second_name;
對錶刪除唯一鍵
alter table students drop index name;
修改字段字義屬性
alter table students modify name char(20);
alter table students2 change name new_name char(20) after id;
alter table students2 change name new_name char(20);
modify : 只可以修改字段定義的屬性
change : 可以修改字段名稱和定義的字段屬性
查看錶狀態
show table status like 'students2'\G
修改表引擎
alter table students2 engine[=]myisam;
查看錶的字段描述
desc students;
查看庫中的所有表
show tables
show tables from mysql;
刪除表
drop table students2;
向表中插入數據
insert weizi value(1,'zhen',30,'F');
insert weizi values(3,'wei',30,'F'),(4,'ping',31,'F');
insert weizi (id,name) value (5,"weizi");
刪除表中的數據
delete from weizi where name="zhen";
delete from weizi where age is null;
delete from weizi where age > 30;
delete from weizi where id >=50 and age <=20;
delete from weizi order by age asc limit 5;
修改表中的字段值
update weizi set age=35 where id=3 and age=30;
update weizi set age=age-5 where age=35;
update weizi age=age-age;
update weizi set age=age-5 where order by id desc limit 10;
update weizi set age=age-15 where name not like 'stu%';
Select操作語句
使用格式
select col1,col2,....from tb1_name [where clause] [order y 'col_name'] [limit [m,]n]
字段表示法
* : 表示所有字段
as : 字段別名, col1 as alias1
where clause
操作符:
==
<
>
<=
>=
!=
between....and...
條件邏輯操作
and
or
not
模糊匹配
like
%
_
rlike 'pattern' : 基於正則表達式匹配
is null
is no null
排序
desc : 降序
asc : 升序
Select示例
select name,age from students where age >30 and age<80;
select name,age from students where age between 30 and 80;
select name from students where name like '%ang%';
select name from students where name rlike '^.*ang.*$;
select name,age from students where age is null;
select name,age form students where age is not null;
select id,name from students order by name;
select id,name from students order by name desc;
權限及授權管理
用戶表示方法:
username@host
管理權限的分類
管理權限
數據庫
表
字段
存儲例程
授權:
授權語法格式
grant pri_type,...on [object_type] db_name.tbl_name to 'user'@'host' [identified by 'PASSWD']
pri_type
all privileges : 表示全部權限
db_name.tbl_name的表示方法:
*.* : 所有庫的所有表
db_name.* : 指定庫的所有表
db_name.tbl_name : 指定庫的特定表
db_name.routine_name : 指定庫上的存儲過程或存儲函數
object_type
table
function
procedure
授權示例:
grant all privileges on mydb.* to 'zhenping'@'172.16.%.%' identified by 'MT8ddd';
取消權限
取消授權語法格式
revoke pri_type,.... on db_name.tb_name from 'user'@'host';
取消授權示例:
revoke all privileges on mydb.* from 'zhenping'@'172.16.%.%';
查看用戶權限
show grants for 'user'@'host';
讓新授權的權限立即生效
flush privileges;
1 Mariadb服務進程啓動時會讀取mysql庫中的所有授權表至內存中;
2 grant和revoke等執行權限操作時會保存於表中,mariadb的服務進程會自動重讀授權表
3 對於不能夠或不能及時重讀授權表,可手動讓服務進程重啓授權表,使用flush privileges
番外往篇
在CentOS 6 上手動編譯安裝mysql
首先關閉之前啓動的mysql服務,並且將其卸載
[root@localhost php.d]# service mysqld stop
[root@localhost ~]# rpm -e mysql-server
warning: /var/log/mysqld.log saved as /var/log/mysqld.log.rpmsave
爲了徹底刪除,我們也要將它產生的日誌文件也給刪了
[root@localhost ~]# rm -f /var/log/mysqld.log.rpmsave
下載mariadb的源碼包( mariadb-5.5.43-linux-x86_64.tar.gz),然後創建一個系統用戶
[root@localhost ~]# groupadd -r mysql
[root@localhost ~]# id mysql
uid=27(mysql) gid=27(mysql) groups=27(mysql)
將源碼包解壓縮至指定的目錄
[root@localhost ~]# tar xf mariadb-5.5.43-linux-x86_64.tar.gz -C /usr/local
爲解壓縮出來的目錄做一個鏈接,因爲我們用到相關文件時,引用的名稱爲mysql
[root@localhost ~]# cd /usr/local
[root@localhost local]# ln -sv mariadb-5.5.43-linux-x86_64 mysql
將mysql目錄下的文件修改其權限
[root@localhost mysql]# chown -R root:mysql ./*
接下來我們就要創建mysql的專用數據存儲目錄了。這個很明顯,存放數據的目錄當然要單獨分區,在此處,我們將它放在LVM2上
我們重新掛載上一個硬盤/dev/sdb,將其分成兩個區,並調整爲8e,即LVM的格式。
[root@localhost ~]# fdisk /dev/sdb
創建完成後,重讀一下分區表
[root@localhost ~]# partx -a /dev/sdb
BLKPG: Device or resource busy
error adding partition 1
BLKPG: Device or resource busy
error adding partition 2
如此便創建成功了,接着我們將這兩個分區只作爲LVM2
[root@localhost ~]# pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created
[root@localhost ~]# pvcreate /dev/sdb2
Physical volume "/dev/sdb2" successfully created
創建vg
[root@localhost ~]# vgcreate myvg /dev/sdb1 /dev/sdb2
Volume group "myvg" successfully created
創建lv
[root@localhost ~]# lvcreate -L10G -n mydata myvg
Logical volume "mydata" created
我們想要在這個lvm上安裝xfs文件系統,所以先安裝這個文件系統所需要的相關文件
[root@localhost ~]# yum install xfsprogs -y
xfs文件系統比ext4有更好的擴展性
[root@localhost ~]# modprobe xfs
[root@localhost ~]# modinfo xfs
filename: /lib/modules/2.6.32-504.el6.x86_64/kernel/fs/xfs/xfs.ko
license: GPL
description: SGI XFS with ACLs, security attributes, large block/inode numbers, no debug enabled
author: Silicon Graphics, Inc.
srcversion: 4392D4D583B9D2781E4F61E
depends: exportfs
vermagic: 2.6.32-504.el6.x86_64 SMP mod_unload modversions
將lvm格式化爲xfs
[root@localhost ~]# mkfs.xfs /dev/myvg/mydata
meta-data=/dev/myvg/mydata isize=256 agcount=4, agsize=655360 blks
= sectsz=512 attr=2, projid32bit=0
data = bsize=4096 blocks=2621440, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
創建文件系統掛載目錄
[root@localhost ~]# mkdir /mydata
將掛載信息添加到配置文件中,使開機時自動掛載
[root@localhost ~]# vim /etc/fstab
/dev/myvg/mydata /mydata xfs defaults 0 0
重讀一下配置文件,使其掛載上
[root@localhost ~]# mount -a
查看掛載信息
[root@localhost ~]# mount
/dev/mapper/myvg-mydata on /mydata type xfs (rw)
在這個目錄下創建一個數據庫目錄
[root@localhost mydata]# mkdir data
修改其屬主屬組
[root@localhost mydata]# chown mysql:mysql data
[root@localhost mydata]# ll
total 0
drwxr-xr-x. 2 mysql mysql 6 Oct 11 03:37 data
回到mysql的目錄
[root@localhost local]# cd /usr/local/mysql/
[root@localhost mysql]# ls scripts/
mysql_install_db
注意這個目錄下的此腳本,它是專門用於生成mysql初始化的
查看這個初始化腳本的相關配置信息
[root@localhost mysql]# scripts/mysql_install_db --help
[root@localhost mysql]# scripts/mysql_install_db --user=mysql --datadir=/mydata/data/
此時查看初始化生成的相關目錄,其實就是庫文件
[root@localhost mysql]# ls /mydata/data
aria_log.00000001 aria_log_control mysql performance_schema test
接着準備mysql的服務腳本
[root@localhost mysql]# cp support-files/mysql.server /etc/rc.d/init.d/mysqld
添加上這個腳本
[root@localhost mysql]# chkconfig --add mysqld
[root@localhost mysql]# chkconfig --list mysqld
mysqld 0:off 1:off 2:on 3:on 4:on 5:on 6:off
接下來就要準備配置文件了,複製一個模板,稍作修改便可成爲配置文件
[root@localhost mysql]# mkdir /etc/mysql
[root@localhost mysql]# cp support-files/my-large.cnf /etc/mysql/my.cnf
對這個配置文件,做一下針對性的修改
[root@localhost mysql]# vim /etc/mysql/my.cnf
其中的配置文件分爲n段
[client] mysqld客戶端要讀取的配置
[mysqld] mysqld服務器端要讀取的配置
我們僅需要在[mysqld]中,稍作修改即可
thread_concurrency = 8
datadir=/mydata/data
innodb_file_per_table=on
skip_name_resolve=on(跳過名稱解析)
說明:mysql每次通過客戶端進行連接時,它都會把ip地址反解成主機名,並在本地做權限檢查,這相當麻煩。所以乾脆跳過,以後主機來訪時,我們僅根據其客戶端來源ip做檢查,授權時也根據ip做授權。
啓動mysql服務
[root@localhost mysql]# service mysqld start
[root@localhost mysql]# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 :::22 :::*
LISTEN 0 128 *:22 *:*
LISTEN 0 128 127.0.0.1:631 *:*
LISTEN 0 128 ::1:631 :::*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 127.0.0.1:6010 *:*
LISTEN 0 128 ::1:6010 :::*
LISTEN 0 50 *:3306 *:*
LISTEN 0 128 :::80 :::*
在/usr/local/mysql/bin中有一些二進制程序
[root@localhost mysql]# ls bin
aria_chk myisam_ftdump mysqlbug mysqld_safe mysql_plugin mysql_upgrade
aria_dump_log myisamlog mysqlcheck mysqldump mysql_secure_installation mysql_waitpid
aria_ftdump myisampack mysql_client_test mysqldumpslow mysql_setpermission mysql_zap
aria_pack my_print_defaults mysql_client_test_embedded mysql_embedded mysqlshow mytop
aria_read_log mysql mysql_config mysql_find_rows mysqlslap perror
innochecksum mysqlaccess mysql_convert_table_format mysql_fix_extensions mysqltest replace
msql2mysql mysqladmin mysqld mysqlhotcopy mysqltest_embedded resolveip
myisamchk mysqlbinlog mysqld_multi mysqlimport mysql_tzinfo_to_sql resolve_stack_dump
查看相關的進程
[root@localhost mysql]# ps aux | grep mysql
root 2734 0.0 0.1 11472 1376 pts/0 S 04:02 0:00
/bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/mydata/data --pid-file=/mydata/data/localhost.localdomain.pid
mysql 3135 0.3 13.2 842784 132716 pts/0 Sl 04:02 0:00
/usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/mydata/data --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/var/log/mysqld.log --pid-file=/mydata/data/localhost.localdomain.pid --socket=/tmp/mysql.sock --port=3306
root 3176 0.0 0.0 103252 836 pts/0 S+ 04:07 0:00 grep mysql
注意:其中含有mysqld-safe程序
講述下/usr/local/bin/mysql,這個命令行使用的相關方法
[root@localhost mysql]# mysql
mysql> use mysql;
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 | |
+------+-----------------------+----------+
6 rows in set (0.00 sec)
設置安全初始化程序,禁止管理員禁止登陸,清空匿名用戶,設置管理員的密碼
[root@localhost mysql]# /usr/local/mysql/bin/mysql_secure_installation
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] Y
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!
此時你用root登錄,會發現已經不能直接登錄了
[root@localhost mysql]# mysql
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
可用這種方式登錄
[root@localhost mysql]# mysql -uroot -p
mysql> use mysql;
mysql> SELECT User,Host,Password FROM user;
+------+-----------+-------------------------------------------+
| User | Host | Password |
+------+-----------+-------------------------------------------+
| root | localhost | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |
| root | 127.0.0.1 | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |
| root | ::1 | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |
+------+-----------+-------------------------------------------+
3 rows in set (0.00 sec)
mysql> status
--------------
mysql Ver 14.14 Distrib 5.1.73, for redhat-linux-gnu (x86_64) using readline 5.1
Connection id: 18
Current database: mysql
Current user: root@localhost
SSL: Not in use
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.5.43-MariaDB-log MariaDB Server
Protocol version: 10
Connection: Localhost via UNIX socket
Server characterset: latin1
Db characterset: latin1
Client characterset: latin1
Conn. characterset: latin1
UNIX socket: /tmp/mysql.sock
Uptime: 20 min 35 sec
Threads: 1 Questions: 38 Slow queries: 0 Opens: 1 Flush tables: 2 Open tables: 27 Queries per second avg: 0.030
--------------
查看命令的相關幫助文檔
mysql> HELP CREATE DATABASE;
mysql> SHOW ENGINES;
mysql> CREATE DATABASE IF NOT EXISTS testdb;
mysql> use testdb;
mysql> CREATE TABLE tb1(id int NOT NULL,name VARCHAR(100) NOT NULL,age tinyint);
mysql> SHOW TABLES;
+------------------+
| Tables_in_testdb |
+------------------+
| tb1 |
+------------------+
1 row in set (0.00 sec)
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| testdb |
+--------------------+
4 rows in set (0.00 sec)
mysql> DESC tb1;
+-------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| id | int(11) | NO | | NULL | |
| name | varchar(100) | NO | | NULL | |
| age | tinyint(4) | YES | | NULL | |
+-------+--------------+------+-----+---------+-------+
3 rows in set (0.02 sec)
9.mysql的基礎命令
登錄進mysql
[root@localhost mysql]# mysql -uroot -predhat
mysql> CREATE DATABASE testdb;
mysql> CREATE TABLE students (id int UNSIGNED NOT NULL PRIMARY KEY,name VARCHAR(20) NOT NULL,age tinyint UNSIGNED);
mysql> DESC students;
+-------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------------------+------+-----+---------+-------+
| id | int(10) unsigned | NO | PRI | NULL | |
| name | varchar(20) | NO | | NULL | |
| age | tinyint(3) unsigned | YES | | NULL | |
+-------+---------------------+------+-----+---------+-------+
3 rows in set (0.00 sec)
或者是單獨定義修飾符表示的內容,即定義聯合式的主鍵
mysql> CREATE TABLE tbl2 (id int UNSIGNED NOT NULL,name VARCHAR(20) NOT NULL,age tinyint UNSIGNED,PRIMARY KEY(id,name));
這裏只要是id,name這兩個鍵的聯合內容不相同即可。
mysql> SHOW TABLE STATUS LIKE 'students'\G;
*************************** 1. row ***************************
Name: students
Engine: InnoDB
Version: 10
Row_format: Compact
Rows: 0
Avg_row_length: 0
Data_length: 16384
Max_data_length: 0
Index_length: 0
Data_free: 0
Auto_increment: NULL
Create_time: 2015-10-11 04:33:41
Update_time: NULL
Check_time: NULL
Collation: latin1_swedish_ci
Checksum: NULL
Create_options:
Comment:
1 row in set (0.00 sec)
ERROR:
No query specified
\G的含義是豎排顯示
在幫助手冊中查看ALTER, CHANGE, MODIFY這三個命令的不同
添加字段
mysql> ALTER TABLE students ADD gender ENUM('m','f');
當修改字段名稱時,對剩下的要有定義
mysql> ALTER TABLE students CHANGE id sid int UNSIGNED NOT NULL;
mysql> DESC students;
+--------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| sid | int(10) unsigned | NO | PRI | NULL | |
| name | varchar(20) | NO | | NULL | |
| age | tinyint(3) unsigned | YES | | NULL | |
| gender | enum('m','f') | YES | | NULL | |
+--------+---------------------+------+-----+---------+-------+
4 rows in set (0.01 sec)
修改惟一鍵
mysql> ALTER TABLE students ADD UNIQUE KEY(name);
mysql> DESC students;
+--------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| sid | int(10) unsigned | NO | PRI | NULL | |
| name | varchar(20) | NO | UNI | NULL | |
| age | tinyint(3) unsigned | YES | | NULL | |
| gender | enum('m','f') | YES | | NULL | |
+--------+---------------------+------+-----+---------+-------+
4 rows in set (0.01 sec)
添加索引
mysql> SHOW INDEXES FROM students\G;
*************************** 1. row ***************************
Table: students
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name: sid
Collation: A
Cardinality: 0
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
Index_comment:
*************************** 2. row ***************************
Table: students
Non_unique: 0
Key_name: name
Seq_in_index: 1
Column_name: name
Collation: A
Cardinality: 0
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
Index_comment:
2 rows in set (0.02 sec)
刪除索引
mysql> ALTER TABLE students DROP age;
mysql> SHOW INDEXES FROM students\G;
mysql> DROP INDEX name ON students;
DML:
mysql> INSERT INTO students VALUES (1,'YangGuo','m');
mysql> SELECT * FROM students;
+-----+---------+--------+
| sid | name | gender |
+-----+---------+--------+
| 1 | YangGuo | m |
+-----+---------+--------+
1 row in set (0.00 sec)
mysql> INSERT INTO students (sid,name) VALUES (3,'ZhangWuji'),(4,'ZhaoMin');
mysql> SELECT * FROM students;
+-----+-----------+--------+
| sid | name | gender |
+-----+-----------+--------+
| 1 | YangGuo | m |
| 3 | ZhangWuji | NULL |
| 4 | ZhaoMin | NULL |
+-----+-----------+--------+
3 rows in set (0.00 sec)
查看創建命令的幫助信息
mysql> HELP DELETE;
Name: 'DELETE'
Description:
Syntax:
Single-table syntax:
DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name
[WHERE where_condition]
[ORDER BY ...]
[LIMIT row_count]
Multiple-table syntax:
DELETE [LOW_PRIORITY] [QUICK] [IGNORE]
tbl_name[.*] [, tbl_name[.*]] ...
FROM table_references
[WHERE where_condition]
Or:
DELETE [LOW_PRIORITY] [QUICK] [IGNORE]
FROM tbl_name[.*] [, tbl_name[.*]] ...
USING table_references
[WHERE where_condition]
mysql> 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]]
mysql> SELECT * FROM students WHERE gender='m';
+-----+---------+--------+
| sid | name | gender |
+-----+---------+--------+
| 1 | YangGuo | m |
+-----+---------+--------+
1 row in set (0.00 sec)
mysql> SELECT * FROM students WHERE gender IS NULL;
+-----+-----------+--------+
| sid | name | gender |
+-----+-----------+--------+
| 3 | ZhangWuji | NULL |
| 4 | ZhaoMin | NULL |
+-----+-----------+--------+
2 rows in set (0.00 sec)
mysql> SELECT * FROM students ORDER BY name DESC LIMIT 1,2;
+-----+-----------+--------+
| sid | name | gender |
+-----+-----------+--------+
| 3 | ZhangWuji | NULL |
| 1 | YangGuo | m |
+-----+-----------+--------+
2 rows in set (0.01 sec)
mysql> SELECT * FROM students WHERE sid>=2 AND sid<=4;
+-----+-----------+--------+
| sid | name | gender |
+-----+-----------+--------+
| 3 | ZhangWuji | NULL |
| 4 | ZhaoMin | NULL |
+-----+-----------+--------+
2 rows in set (0.00 sec)
mysql> SELECT * FROM students WHERE sid BETWEEN 2 AND 4;
+-----+-----------+--------+
| sid | name | gender |
+-----+-----------+--------+
| 3 | ZhangWuji | NULL |
| 4 | ZhaoMin | NULL |
+-----+-----------+--------+
2 rows in set (0.00 sec)
mysql> SELECT * FROM students WHERE name LIKE 'z%';
+-----+-----------+--------+
| sid | name | gender |
+-----+-----------+--------+
| 3 | ZhangWuji | NULL |
| 4 | ZhaoMin | NULL |
+-----+-----------+--------+
2 rows in set (0.00 sec)
mysql> SELECT * FROM students WHERE name RLIKE '.*[A-G]u.*';
+-----+---------+--------+
| sid | name | gender |
+-----+---------+--------+
| 1 | YangGuo | m |
+-----+---------+--------+
1 row in set (0.00 sec)
mysql> SELECT sid as stuid,name as stuname FROM students;
+-------+-----------+
| stuid | stuname |
+-------+-----------+
| 1 | YangGuo |
| 3 | ZhangWuji |
| 4 | ZhaoMin |
+-------+-----------+
3 rows in set (0.00 sec)
mysql> HELP UPDATE
Name: 'UPDATE'
Description:
Syntax:
Single-table syntax:
UPDATE [LOW_PRIORITY] [IGNORE] table_reference
SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
[WHERE where_condition]
[ORDER BY ...]
[LIMIT row_count]
創建用戶
mysql> CREATE USER 'wpuser'@'%' IDENTIFIED BY 'wppasswd';
mysql> use mysql;
查看存儲用戶的信息表
mysql> SELECT User,Host,Password FROM user;
+--------+-----------+-------------------------------------------+
| User | Host | Password |
+--------+-----------+-------------------------------------------+
| root | localhost | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |
| root | 127.0.0.1 | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |
| root | ::1 | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |
| wpuser | % | *7CD61EFBFDDDBD978EA9017F2A26A59DE4589025 |
+--------+-----------+-------------------------------------------+
4 rows in set (0.01 sec)
這樣任意主機,就可以通過wpuser進入mysql
我們通過192.168.1.110連接本機的mysql
[root@localhost ~]# mysql -uwpuser -h192.168.1.109 -p
注意:如果連接不上,注意查看一下防火牆
MariaDB [(none)]> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
+--------------------+
1 row in set (0.04 sec)
MariaDB [(none)]> HELP GRANT;
Name: 'GRANT'
Description:
Syntax:
GRANT
priv_type [(column_list)]
[, priv_type [(column_list)]] ...
ON [object_type] priv_level
TO user_specification [, user_specification] ...
[REQUIRE {NONE | ssl_option [[AND] ssl_option] ...}]
[WITH with_option ...]
GRANT PROXY ON user_specification
TO user_specification [, user_specification] ...
[WITH GRANT OPTION]
object_type:
TABLE
| FUNCTION
| PROCEDURE
priv_level:
*
| *.*
| db_name.*
| db_name.tbl_name
| tbl_name
| db_name.routine_name
user_specification:
user
[
IDENTIFIED BY [PASSWORD] 'password'
| IDENTIFIED WITH auth_plugin [AS 'auth_string']
]
ssl_option:
SSL
| X509
| CIPHER 'cipher'
| ISSUER 'issuer'
| SUBJECT 'subject'
with_option:
GRANT OPTION
| MAX_QUERIES_PER_HOUR count
| MAX_UPDATES_PER_HOUR count
| MAX_CONNECTIONS_PER_HOUR count
| MAX_USER_CONNECTIONS count
MariaDB [(none)]> HELP SHOW GRANTS;
Name: 'SHOW GRANTS'
Description:
Syntax:
SHOW GRANTS [FOR user]
MariaDB [(none)]> SHOW GRANTS FOR 'wpuser'@'%';
+-------------------------------------------------------------------------------------------------------+
| Grants for wpuser@% |
+-------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'wpuser'@'%' IDENTIFIED BY PASSWORD '*7CD61EFBFDDDBD978EA9017F2A26A59DE4589025' |
+-------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> SHOW GRANTS FOR 'root'@'localhost';
mysql> SHOW GRANTS FOR CURRENT_USER;
mysql> GRANT SELECT,DELETE ON testdb.* TO 'testdb'@'%' IDENTIFIED BY 'testpass';
以192.168.1.110訪問數據庫
[root@localhost ~]# mysql -utestdb -h192.168.1.109 -p
MariaDB [(none)]> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| testdb |
+--------------------+
2 rows in set (0.00 sec)
MariaDB [(none)]> use testdb;
MariaDB [testdb]> SHOW GRANTS FOR CURRENT_USER;
+-------------------------------------------------------------------------------------------------------+
| Grants for testdb@% |
+-------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'testdb'@'%' IDENTIFIED BY PASSWORD '*00E247AC5F9AF26AE0194B41E1E769DEE1429A29' |
| GRANT SELECT, DELETE ON `testdb`.* TO 'testdb'@'%' |
+-------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
MariaDB [testdb]> CREATE TABLE tbl2(id int);
ERROR 1142 (42000): CREATE command denied to user 'testdb'@'192.168.1.110' for table 'tbl2'
此時會發現,因爲我們之前設定的原因,當前用戶沒有權限創建表
MariaDB [testdb]> DELETE FROM students WHERE sid=4;
Query OK, 1 row affected (0.01 sec)
回收權限
MariaDB [testdb]> REVOKE DELETE ON testdb.* FROM 'testdb'@'%';
ERROR 1044 (42000): Access denied for user 'testdb'@'%' to database 'testdb'
發現自己沒有權限回收權限,只有以管理員的權限纔可以