更新了Linux和数据库文档
jackfrued
parent
243c42cff0
commit
0da68f50a0
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@ -655,12 +655,45 @@ Linux系统的命令通常都是如下所示的格式：
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#### 磁盘管理
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1. 列出文件系统的磁盘使用状况 - **df**。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# df -h
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Filesystem Size Used Avail Use% Mounted on
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/dev/vda1 40G 5.0G 33G 14% /
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devtmpfs 486M 0 486M 0% /dev
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tmpfs 497M 0 497M 0% /dev/shm
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tmpfs 497M 356K 496M 1% /run
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tmpfs 497M 0 497M 0% /sys/fs/cgroup
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tmpfs 100M 0 100M 0% /run/user/0
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```
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2. 磁盘分区表操作 - **fdisk**。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# fdisk -l
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Disk /dev/vda: 42.9 GB, 42949672960 bytes, 83886080 sectors
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Units = sectors of 1 * 512 = 512 bytes
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Sector size (logical/physical): 512 bytes / 512 bytes
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I/O size (minimum/optimal): 512 bytes / 512 bytes
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Disk label type: dos
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Disk identifier: 0x000a42f4
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Device Boot Start End Blocks Id System
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/dev/vda1 * 2048 83884031 41940992 83 Linux
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Disk /dev/vdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
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Units = sectors of 1 * 512 = 512 bytes
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Sector size (logical/physical): 512 bytes / 512 bytes
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I/O size (minimum/optimal): 512 bytes / 512 bytes
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```
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3. 格式化文件系统 - **mkfs**。
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4. 文件系统检查 - **fsck**。
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5. 挂载/卸载 - **mount** / **umount**。
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### 编辑器vim
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### 编辑器 - vim
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1. 启动vim。可以通过`vi`或`vim`命令来启动vim，启动时可以指定文件名来打开一个文件，如果没有指定文件名，也可以在保存的时候指定文件名。
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@ -759,19 +792,11 @@ Linux系统的命令通常都是如下所示的格式：
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### 环境变量
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1. HOME
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2. SHELL
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3. HISTSIZE
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4. RANDOM
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5. PATH
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### 软件安装和配置
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#### 使用包管理工具
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1. yum - Yellowdog Updater Modified。
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1. **yum** - Yellowdog Updater Modified。
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- `yum search`：搜索软件包，例如`yum search nginx`。
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- `yum list installed`：列出已经安装的软件包，例如`yum list installed | grep zlib`。
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- `yum install`：安装软件包，例如`yum install nginx`。
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@ -779,7 +804,7 @@ Linux系统的命令通常都是如下所示的格式：
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- `yum update`：更新软件包，例如`yum update`可以更新所有软件包，而`yum update tar只会更新tar。
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- `yum check-update`：检查有哪些可以更新的软件包。
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- `yum info`：显示软件包的相关信息，例如`yum info nginx`。
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2. rpm - Redhat Package Manager。
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2. **rpm** - Redhat Package Manager。
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- 安装软件包：`rpm -ivh <packagename>.rpm`。
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- 移除软件包：`rpm -e <packagename>`。
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- 查询软件包：`rpm -qa`，例如可以用`rpm -qa | grep mysql`来检查是否安装了MySQL相关的软件包。
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@ -823,6 +848,14 @@ Description : Nginx is a web server and a reverse proxy server for HTTP, SMTP, P
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nginx version: nginx/1.12.2
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```
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移除Nginx。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# nginx -s stop
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# yum -y remove nginx
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```
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下面以MySQL为例，演示如何使用rpm安装软件。要安装MySQL需要先到[MySQL官方网站](https://www.mysql.com/)下载对应的[RPM文件](https://dev.mysql.com/downloads/mysql/)，当然要选择和你使用的Linux系统对应的版本。MySQL现在是Oracle公司旗下的产品，在MySQL被收购后，MySQL的作者重新制作了一个MySQL的分支MariaDB，可以通过yum进行安装。如果要安装MySQL需要先通过yum删除`mariadb-libs`这个可能会跟MySQL底层库冲突的库，然后还需要安装一个名为`libaio`的依赖库。
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```Shell
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@ -834,26 +867,19 @@ mysql-community-libs-5.7.22-1.el7.x86_64.rpm
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mysql-community-server-5.7.22-1.el7.x86_64.rpm
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# yum -y remove mariadb-libs
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# yum -y install libaio
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# rpm -ivh mysql-community-common-5.7.22-1.el7.x86_64.rpm
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warning: mysql-community-common-5.7.22-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
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Preparing... ################################# [100%]
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package mysql-community-common-5.7.22-1.el7.x86_64 is already installed
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# rpm -ivh mysql-community-libs-5.7.22-1.el7.x86_64.rpm
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warning: mysql-community-libs-5.7.22-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
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Preparing... ################################# [100%]
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package mysql-community-libs-5.7.22-1.el7.x86_64 is already installed
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# rpm -ivh mysql-community-client-5.7.22-1.el7.x86_64.rpm
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# ls | xargs rpm -ivh
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warning: mysql-community-client-5.7.22-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
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Preparing... ################################# [100%]
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package mysql-community-client-5.7.22-1.el7.x86_64 is already installed
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# rpm -ivh mysql-community-server-5.7.22-1.el7.x86_64.rpm
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warning: mysql-community-server-5.7.22-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
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Preparing... ################################# [100%]
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package mysql-community-server-5.7.22-1.el7.x86_64 is already installed
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# mysqld --version
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mysqld Ver 5.7.22 for Linux on x86_64 (MySQL Community Server (GPL))
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[root@iZwz97tbgo9lkabnat2lo8Z mysql]# mysql --version
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mysql Ver 14.14 Distrib 5.7.22, for Linux (x86_64) using EditLine wrapper
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...
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```
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> 说明：由于MySQL和[MariaDB](https://mariadb.org/)的底层依赖库是有冲突的，所以上面我们首先用`yum`移除了名为mariadb-libs的依赖库并安装了名为libaio的依赖库。由于我们将安装MySQL所需的rpm文件放在一个独立的目录中，所以可以通过`ls`命令查看到安装文件并用`xargs`将`ls`的输出作为参数交给`rpm -ivh`来进行安装。关于MySQL和MariaDB之间的关系，可以阅读[维基百科](https://zh.wikipedia.org/wiki/MariaDB)上关于MariaDB的介绍。
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移除安装的MySQL。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# rpm -qa | grep mysql | xargs rpm -e
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```
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#### 下载解压配置环境变量
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@ -957,15 +983,6 @@ build environment:
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redis-cli 3.2.12
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```
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### 进程和性能
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1. top
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2. pmap
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3. sar
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4. free
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5. iostat
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6. gprof
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### 配置服务
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1. 启动服务。
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@ -1014,16 +1031,45 @@ build environment:
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# crontab -e
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* * * * * echo "hello, world!" >> /root/hello.txt
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59 23 * * * rm -f /root/*.log
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```
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> 说明：输入`crontab -e`命令会打开vim来编辑Cron表达式并指定触发的任务，上面我们定制了两个计划任务，一个是每分钟向/root目录下的hello.txt中追加输出`hello, world!`；另一个是每天23时59分执行删除/root目录下以log为后缀名的文件。如果不知道Cron表达式如何书写，可以参照/etc/crontab文件中的提示（下面会讲到）或者用谷歌或百度搜索一下，也可以使用Cron表达式在线生成器来生成Cron表达式。
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2. crontab相关文件。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# cd /etc
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[root@iZwz97tbgo9lkabnat2lo8Z etc]# ls -l | grep cron
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-rw-------. 1 root root 541 Aug 3 2017 anacrontab
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drwxr-xr-x. 2 root root 4096 Mar 27 11:56 cron.d
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drwxr-xr-x. 2 root root 4096 Mar 27 11:51 cron.daily
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-rw-------. 1 root root 0 Aug 3 2017 cron.deny
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drwxr-xr-x. 2 root root 4096 Mar 27 11:50 cron.hourly
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drwxr-xr-x. 2 root root 4096 Jun 10 2014 cron.monthly
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-rw-r--r-- 1 root root 493 Jun 23 15:09 crontab
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drwxr-xr-x. 2 root root 4096 Jun 10 2014 cron.weekly
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[root@iZwz97tbgo9lkabnat2lo8Z etc]# vim crontab
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1 SHELL=/bin/bash
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2 PATH=/sbin:/bin:/usr/sbin:/usr/bin
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3 MAILTO=root
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4
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5 # For details see man 4 crontabs
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6
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7 # Example of job definition:
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8 # .---------------- minute (0 - 59)
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9 # | .------------- hour (0 - 23)
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10 # | | .---------- day of month (1 - 31)
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11 # | | | .------- month (1 - 12) OR jan,feb,mar,apr ...
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12 # | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
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13 # | | | | |
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14 # * * * * * user-name command to be executed
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```
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通过修改`/etc`目录下的crontab文件也能够定制计划任务。
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### 网络访问和管理
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1. 通过网络获取资源 - **wget**。
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@ -1116,13 +1162,158 @@ build environment:
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- `bye`/`exit`/`quit`：退出sftp。
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### 进程管理
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1. **ps** - 查询进程。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# ps -ef
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UID PID PPID C STIME TTY TIME CMD
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root 1 0 0 Jun23 ? 00:00:05 /usr/lib/systemd/systemd --switched-root --system --deserialize 21
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root 2 0 0 Jun23 ? 00:00:00 [kthreadd]
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...
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# ps -ef | grep mysqld
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root 4943 4581 0 22:45 pts/0 00:00:00 grep --color=auto mysqld
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mysql 25257 1 0 Jun25 ? 00:00:39 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
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```
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2. **kill** - 终止进程。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# kill 1234
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# kill -9 1234
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```
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例子：用一条命令强制终止正在运行的Redis进程。
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```Shell
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ps -ef | grep redis | grep -v grep | awk '{print $2}' | xargs kill
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```
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3. 将进程置于后台运行。
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- `Ctrl+Z`
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- `&`
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# mongod &
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# redis-server
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...
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^Z
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[4]+ Stopped redis-server
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```
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4. **jobs** - 查询后台进程。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# jobs
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[2] Running mongod &
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[3]- Stopped cat
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[4]+ Stopped redis-server
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```
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5. **bg** - 让进程在后台继续运行。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# bg %4
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[4]+ redis-server &
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# jobs
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[2] Running mongod &
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[3]+ Stopped cat
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[4]- Running redis-server &
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```
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6. **fg** - 将后台进程置于前台。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# fg %4
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redis-server
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^C5554:signal-handler (1530025281) Received SIGINT scheduling shutdown...
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5554:M 26 Jun 23:01:21.413 # User requested shutdown...
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5554:M 26 Jun 23:01:21.413 * Saving the final RDB snapshot before exiting.
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5554:M 26 Jun 23:01:21.415 * DB saved on disk
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5554:M 26 Jun 23:01:21.415 # Redis is now ready to exit, bye bye...
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```
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> 说明：置于前台的进程可以使用`Ctrl+C`来终止它。
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7. **top** - 进程监控。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# top
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top - 23:04:23 up 3 days, 14:10, 1 user, load average: 0.00, 0.01, 0.05
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Tasks: 65 total, 1 running, 64 sleeping, 0 stopped, 0 zombie
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%Cpu(s): 0.3 us, 0.3 sy, 0.0 ni, 99.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
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KiB Mem : 1016168 total, 191060 free, 324700 used, 500408 buff/cache
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KiB Swap: 0 total, 0 free, 0 used. 530944 avail Mem
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...
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```
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### 系统性能
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1. 查看系统活动信息 - **sar**。
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2. 查看内存使用情况 - **free**。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# free
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total used free shared buff/cache available
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Mem: 1016168 323924 190452 356 501792 531800
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Swap: 0 0 0
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```
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3. 查看进程使用内存状况 - **pmap**。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# ps
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PID TTY TIME CMD
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4581 pts/0 00:00:00 bash
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5664 pts/0 00:00:00 ps
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# pmap 4581
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4581: -bash
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0000000000400000 884K r-x-- bash
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00000000006dc000 4K r---- bash
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00000000006dd000 36K rw--- bash
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00000000006e6000 24K rw--- [ anon ]
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0000000001de0000 400K rw--- [ anon ]
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00007f82fe805000 48K r-x-- libnss_files-2.17.so
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00007f82fe811000 2044K ----- libnss_files-2.17.so
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...
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```
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4. 报告设备CPU和I/O统计信息 - **iostat**。
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```Shell
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[root@iZwz97tbgo9lkabnat2lo8Z ~]# iostat
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Linux 3.10.0-693.11.1.el7.x86_64 (iZwz97tbgo9lkabnat2lo8Z) 06/26/2018 _x86_64_ (1 CPU)
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avg-cpu: %user %nice %system %iowait %steal %idle
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0.79 0.00 0.20 0.04 0.00 98.97
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Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
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vda 0.85 6.78 21.32 2106565 6623024
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vdb 0.00 0.01 0.00 2088 0
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```
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### Shell和Shell编程
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#### 环境变量
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1. HOME
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2. SHELL
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3. HISTSIZE
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4. RANDOM
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5. PATH
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### 其他内容
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1. awk
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2. sed
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3. xargs
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@ -9,12 +9,16 @@
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- 具体表象：用二维表（有行和列）组织数据。
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- 编程语言：结构化查询语言（SQL）。
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4. E-R图。
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- 实体 - 矩形框
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- 属性 - 椭圆框
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- 关系 - 菱形框
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- 重数 - 1:1 / 1:N / M:N
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5. 关系型数据库产品。
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- Oracle
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- DB2
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- SQL Server
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- MySQL
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- SQLite
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- [Oracle](https://www.oracle.com/index.html)
|
||||
- [DB2](https://www.ibm.com/analytics/us/en/db2/)
|
||||
- [SQL Server](https://www.microsoft.com/en-us/sql-server/)
|
||||
- [MySQL](https://www.mysql.com/)
|
||||
- [SQLite](https://www.sqlite.org/index.html)
|
||||
|
||||
### MySQL简介
|
||||
|
||||
|
|
@ -27,120 +31,164 @@
|
|||
|
||||
```SQL
|
||||
|
||||
-- 如果存在SRS数据库就删除
|
||||
-- 创建数据库SRS
|
||||
drop database if exists SRS;
|
||||
|
||||
-- 创建学生选课系统数据库SRS并指定默认字符集为UTF8
|
||||
create database SRS default charset utf8;
|
||||
|
||||
-- 切换至SRS数据库
|
||||
-- 切换到SRS
|
||||
use SRS;
|
||||
|
||||
-- 查看当前数据库中所有表
|
||||
show tables;
|
||||
|
||||
-- 创建学生表TbStudent
|
||||
create table TbStudent
|
||||
-- 创建学院表
|
||||
create table tb_college
|
||||
(
|
||||
stuid integer not null,
|
||||
stuname varchar(20) not null,
|
||||
stusex bit default 1,
|
||||
stubirth datetime not null,
|
||||
stutel char(11),
|
||||
stuaddr varchar(255),
|
||||
stuphoto longblob,
|
||||
collid int not null auto_increment comment '学院编号',
|
||||
collname varchar(50) not null comment '学院名称',
|
||||
collmaster varchar(20) not null comment '院长姓名',
|
||||
collweb varchar(511) default '' comment '学院网站',
|
||||
primary key (collid)
|
||||
);
|
||||
|
||||
-- 添加唯一性约束
|
||||
alter table tb_college add constraint uni_college_collname unique (collname);
|
||||
-- alter table tb_college drop index uni_college_collname;
|
||||
|
||||
-- 创建学生表
|
||||
create table tb_student
|
||||
(
|
||||
stuid int not null comment '学号',
|
||||
stuname varchar(20) not null comment '学生姓名',
|
||||
stusex bit default 1 comment '性别',
|
||||
stubirth date not null comment '出生日期',
|
||||
stuaddr varchar(255) default '' comment '籍贯',
|
||||
collid int not null comment '所属学院编号',
|
||||
primary key (stuid)
|
||||
);
|
||||
|
||||
-- 修改学生表删除stutel列
|
||||
alter table TbStudent drop column stutel;
|
||||
-- 添加外键约束
|
||||
alter table tb_student add constraint fk_student_collid foreign key (collid) references tb_college (collid);
|
||||
|
||||
-- 查看学生表结构
|
||||
desc TbStudent;
|
||||
|
||||
-- 如果表TbCourse已经存在就删除它
|
||||
drop table if exists TbCourse;
|
||||
|
||||
-- 创建课程表TbCourse
|
||||
create table TbCourse
|
||||
-- 创建教师表
|
||||
create table tb_teacher
|
||||
(
|
||||
cosid integer not null,
|
||||
cosname varchar(50) not null,
|
||||
coscredit tinyint not null,
|
||||
cosintro varchar(255)
|
||||
teacherid int not null comment '教师工号',
|
||||
tname varchar(20) not null comment '教师姓名',
|
||||
ttitle varchar(10) default '' comment '职称',
|
||||
collid int not null comment '所属学院编号'
|
||||
);
|
||||
|
||||
-- 给课程表设置主键约束
|
||||
alter table TbCourse add constraint pk_course primary key (cosid);
|
||||
-- 添加主键约束
|
||||
alter table tb_teacher add constraint pk_teacher primary key (teacherid);
|
||||
|
||||
-- 创建学生选课记录表TbSC
|
||||
create table TbSC
|
||||
-- 添加外键约束
|
||||
alter table tb_teacher add constraint fk_teacher_collid foreign key (collid) references tb_college (collid);
|
||||
|
||||
-- 创建课程表
|
||||
create table tb_course
|
||||
(
|
||||
scid integer primary key auto_increment,
|
||||
sid integer not null,
|
||||
cid integer,
|
||||
scdate datetime not null,
|
||||
score float
|
||||
courseid int not null comment '课程编号',
|
||||
cname varchar(50) not null comment '课程名称',
|
||||
ccredit tinyint not null comment '学分',
|
||||
tid int not null comment '教师工号',
|
||||
primary key (courseid)
|
||||
);
|
||||
|
||||
-- 给表TbSC添加外键约束
|
||||
alter table TbSC add constraint fk_sid foreign key (sid) references TbStudent (stuid) on delete cascade on update cascade;
|
||||
alter table TbSC add constraint fk_cid foreign key (cid) references TBCourse (cosid);
|
||||
-- 添加外键约束
|
||||
alter table tb_course add constraint fk_course_tid foreign key (tid) references tb_teacher (teacherid);
|
||||
|
||||
-- 创建学生选课表
|
||||
create table tb_score
|
||||
(
|
||||
scid int not null auto_increment comment '选课编号',
|
||||
sid int not null comment '学号',
|
||||
cid int not null comment '课程编号',
|
||||
selectdate datetime comment '选课时间日期',
|
||||
score decimal(4,1) comment '考试成绩',
|
||||
primary key (scid)
|
||||
);
|
||||
|
||||
-- 添加检查约束(MySQL中检查约束不生效)
|
||||
alter table tb_score add constraint ck_score_score check (score between 0 and 100);
|
||||
|
||||
-- 添加外键约束
|
||||
alter table tb_score add constraint fk_score_sid foreign key (sid) references tb_student (stuid);
|
||||
alter table tb_score add constraint fk_score_cid foreign key (cid) references tb_course (courseid);
|
||||
```
|
||||
|
||||
2. DML
|
||||
|
||||
```SQL
|
||||
|
||||
-- 添加学生记录
|
||||
insert into TbStudent values (1001, '张三丰', default, '1978-1-1', '成都市一环路西二段17号', null);
|
||||
insert into TbStudent (stuid, stuname, stubirth) values (1002, '郭靖', '1980-2-2');
|
||||
insert into TbStudent (stuid, stuname, stusex, stubirth, stuaddr) values (1003, '黄蓉', 0, '1982-3-3', '成都市二环路南四段123号');
|
||||
insert into TbStudent values (1004, '张无忌', 1, '1990-4-4', null, null);
|
||||
insert into TbStudent values
|
||||
(1005, '丘处机', 1, '1983-5-5', '北京市海淀区宝盛北里西区28号', null),
|
||||
(1006, '王处一', 1, '1985-6-6', '深圳市宝安区宝安大道5010号', null),
|
||||
(1007, '刘处玄', 1, '1987-7-7', '郑州市金水区纬五路21号', null),
|
||||
(1008, '孙不二', 0, '1989-8-8', '武汉市光谷大道61号', null),
|
||||
(1009, '平一指', 1, '1992-9-9', '西安市雁塔区高新六路52号', null),
|
||||
(1010, '老不死', 1, '1993-10-10', '广州市天河区元岗路310号', null),
|
||||
(1011, '王大锤', 0, '1994-11-11', null, null),
|
||||
(1012, '隔壁老王', 1, '1995-12-12', null, null),
|
||||
(1013, '郭啸天', 1, '1977-10-25', null, null);
|
||||
-- 插入学院数据
|
||||
insert into tb_college
|
||||
(collname, collmaster, collweb) values
|
||||
('计算机学院', '左冷禅', 'http://www.abc.com'),
|
||||
('外国语学院', '岳不群', 'http://www.xyz.com'),
|
||||
('经济管理学院', '风清扬', 'http://www.foo.com');
|
||||
|
||||
-- 删除学生记录
|
||||
delete from TbStudent where stuid=1004;
|
||||
-- 插入学生数据
|
||||
insert into tb_student
|
||||
(stuid, stuname, stusex, stubirth, stuaddr, collid) values
|
||||
(1001, '向问天', 1, '1990-3-4', '四川成都', 1),
|
||||
(1002, '任我行', 1, '1992-2-2', '湖南长沙', 1),
|
||||
(1033, '任盈盈', 0, '1989-12-3', '湖南长沙', 1),
|
||||
(1572, '余沧海', 1, '1993-7-19', '四川成都', 1),
|
||||
(1378, '岳灵珊', 0, '1995-8-12', '四川绵阳', 1),
|
||||
(1954, '林平之', 1, '1994-9-20', '福建莆田', 1),
|
||||
(2035, '令狐冲', 1, '1988-6-30', '陕西咸阳', 2),
|
||||
(3011, '林震南', 1, '1985-12-12', '福建莆田', 3),
|
||||
(3755, '龙傲天', 1, '1993-1-25', '广东东莞', 3),
|
||||
(3923, '向天问', 0, '1985-4-17', '四川成都', 3),
|
||||
(2177, '隔壁老王', 1, '1989-11-27', '四川成都', 2);
|
||||
|
||||
-- 更新学生记录
|
||||
update TbStudent set stubirth='1980-12-12', stuaddr='上海市宝山区同济支路199号' where stuid=1002;
|
||||
-- 插入老师数据
|
||||
insert into tb_teacher
|
||||
(teacherid, tname, ttitle, collid) values
|
||||
(1122, '张三丰', '教授', 1),
|
||||
(1133, '宋远桥', '副教授', 1),
|
||||
(1144, '杨逍', '副教授', 1),
|
||||
(2255, '范遥', '副教授', 2),
|
||||
(3366, '韦一笑', '讲师', 3);
|
||||
|
||||
-- 添加课程记录
|
||||
insert into TbCourse values
|
||||
(1111, 'C语言程序设计', 3, '大神级讲师授课需要抢座'),
|
||||
(2222, 'Java程序设计', 3, null),
|
||||
(3333, '数据库概论', 2, null),
|
||||
(4444, '操作系统原理', 4, null);
|
||||
-- 插入课程数据
|
||||
insert into tb_course
|
||||
(courseid, cname, ccredit, tid) values
|
||||
(1111, 'Python程序设计', 3, 1122),
|
||||
(2222, 'Web前端开发', 2, 1122),
|
||||
(3333, '操作系统', 4, 1122),
|
||||
(4444, '计算机网络', 2, 1133),
|
||||
(5555, '编译原理', 4, 1144),
|
||||
(6666, '算法和数据结构', 3, 1144),
|
||||
(7777, '经贸法语', 3, 2255),
|
||||
(8888, '成本会计', 2, 3366),
|
||||
(9999, '审计', 3, 3366);
|
||||
|
||||
-- 添加学生选课记录
|
||||
insert into TbSC values
|
||||
(default, 1001, 1111, '2016-9-1', 95),
|
||||
(default, 1002, 1111, '2016-9-1', 94),
|
||||
(default, 1001, 2222, now(), null),
|
||||
(default, 1001, 3333, '2017-3-1', 85),
|
||||
(default, 1001, 4444, now(), null),
|
||||
(default, 1002, 4444, now(), null),
|
||||
(default, 1003, 2222, now(), null),
|
||||
(default, 1003, 3333, now(), null),
|
||||
(default, 1005, 2222, now(), null),
|
||||
(default, 1006, 1111, now(), null),
|
||||
(default, 1006, 2222, '2017-3-1', 80),
|
||||
(default, 1006, 3333, now(), null),
|
||||
(default, 1006, 4444, now(), null),
|
||||
(default, 1007, 1111, '2016-9-1', null),
|
||||
(default, 1007, 3333, now(), null),
|
||||
(default, 1007, 4444, now(), null),
|
||||
(default, 1008, 2222, now(), null),
|
||||
(default, 1010, 1111, now(), null);
|
||||
-- 插入选课数据
|
||||
insert into tb_score
|
||||
(sid, cid, selectdate, score) values
|
||||
(1001, 1111, now(), 95),
|
||||
(1001, 2222, now(), 87.5),
|
||||
(1001, 3333, now(), 100),
|
||||
(1001, 4444, now(), null),
|
||||
(1001, 6666, now(), 100),
|
||||
(1002, 1111, now(), 65),
|
||||
(1002, 5555, now(), 42),
|
||||
(1033, 1111, now(), 92.5),
|
||||
(1033, 4444, now(), 78),
|
||||
(1033, 5555, now(), 82.5),
|
||||
(1572, 1111, now(), 78),
|
||||
(1378, 1111, now(), 82),
|
||||
(1378, 7777, now(), 65.5),
|
||||
(2035, 7777, now(), 88),
|
||||
(2035, 9999, now(), 70),
|
||||
(3755, 1111, now(), 72.5),
|
||||
(3755, 8888, now(), 93),
|
||||
(3755, 9999, now(), null);
|
||||
|
||||
-- 删除数据
|
||||
delete from tb_student where stuid=2177;
|
||||
|
||||
-- 更新数据
|
||||
update tb_score set score=null where sid=1002 and cid=1111;
|
||||
```
|
||||
|
||||
3. DQL
|
||||
|
|
@ -148,90 +196,113 @@
|
|||
```SQL
|
||||
|
||||
-- 查询所有学生信息
|
||||
select * from TbStudent;
|
||||
select * from tb_student;
|
||||
select stuid, stuname, stusex, stubirth, stuaddr, collid
|
||||
from tb_student;
|
||||
|
||||
-- 查询所有课程名称及学分(投影和别名)
|
||||
select cosname as `课程名称`, coscredit as `学分` from TbCourse;
|
||||
select cname as 课程名称, ccredit as 学分 from tb_course;
|
||||
|
||||
-- 查询所有女学生的姓名和出生日期(筛选)
|
||||
select stuname, stubirth from TbStudent where stusex=0;
|
||||
select stuname, stubirth from tb_student where stusex=0;
|
||||
|
||||
-- 查询所有80后学生的姓名、性别和出生日期(筛选)
|
||||
select stuname as `姓名`, if(stusex, '男', '女') as `性别`, stubirth as `出生日期` from TbStudent where stubirth between '1980-1-1' and '1989-12-31';
|
||||
-- 查询所有80后女学生的姓名、性别(显示成'女')和出生日期(筛选)
|
||||
select stuname, '女' as stusex, stubirth from tb_student
|
||||
where stubirth between '1980-1-1' and '1989-12-31' and stusex=0;
|
||||
|
||||
-- 查询姓王的学生姓名和性别(模糊)
|
||||
select stuname, stusex from TbStudent where stuname like '王%';
|
||||
-- 查询姓“林”的学生姓名和性别(模糊)
|
||||
select stuname, if(stusex, '男', '女') as stusex
|
||||
from tb_student where stuname like '林%';
|
||||
|
||||
-- 查询姓郭名字总共两个字的学生的姓名(模糊)
|
||||
select stuname from TbStudent where stuname like '郭_';
|
||||
-- 查询姓“张”名字总共两个字的老师的姓名和职称(模糊)
|
||||
select tname from tb_teacher where tname like '张_';
|
||||
|
||||
-- 查询姓郭名字总共三个字的学生的姓名(模糊)
|
||||
select stuname from TbStudent where stuname like '郭__';
|
||||
-- 查询姓“张”名字总共三个字的老师的姓名和职称(模糊)
|
||||
select tname, ttitle from tb_teacher where tname like '张__';
|
||||
|
||||
-- 查询名字中有王字的学生的姓名(模糊)
|
||||
select stuname from TbStudent where stuname like '%王%';
|
||||
-- 查询名字中有“天”字的学生的姓名(模糊)
|
||||
select stuname from tb_student where stuname like '%天%';
|
||||
|
||||
-- 查询没有录入家庭住址和照片的学生姓名(多条件筛选和空值处理)
|
||||
select stuname from TbStudent where stuaddr is null and stuphoto is null;
|
||||
-- 查询学生的籍贯
|
||||
select distinct stuaddr from tb_student
|
||||
where stuaddr<>'' and stuaddr is not null;
|
||||
|
||||
-- 查询学生选课的所有日期(去重)
|
||||
select distinct scdate from TbSC;
|
||||
-- 查询男学生的姓名和生日按年龄从大到小排列(排序)
|
||||
select stuname, stubirth from tb_student
|
||||
where stusex=1 order by stubirth asc;
|
||||
|
||||
-- 查询学生的姓名和生日按年龄从大到小排列(排序)
|
||||
select stuname, stubirth from TbStudent order by stubirth;
|
||||
|
||||
-- 查询所有录入了家庭住址的男学生的姓名、出生日期和家庭住址按年龄从小到大排列(多条件筛选和排序)
|
||||
select stuname, stubirth, stuaddr from TbStudent where stusex=1 and stuaddr is not null order by stubirth desc;
|
||||
|
||||
-- 查询年龄最大的学生的出生日期(聚合函数)
|
||||
select min(stubirth) from TbStudent;
|
||||
|
||||
-- 查询年龄最小的学生的出生日期(聚合函数)
|
||||
select max(stubirth) from TbStudent;
|
||||
-- 查询年龄最大/最小的学生的出生日期(聚合函数)
|
||||
select min(stubirth) from tb_student;
|
||||
select max(stubirth) from tb_student;
|
||||
-- 查询学生/男学生/女学生的总人数
|
||||
select count(stuid) from tb_student;
|
||||
select count(stuid) from tb_student where stusex=1;
|
||||
select count(stuid) from tb_student where stusex=0;
|
||||
-- 查询1111课程的平均分/最低分/最高分/选课人数/考试人数
|
||||
select avg(score) from tb_score where cid=1111;
|
||||
select min(score) from tb_score where cid=1111;
|
||||
select max(score) from tb_score where cid=1111;
|
||||
select count(sid) from tb_score where cid=1111;
|
||||
select count(score) from tb_score where cid=1111;
|
||||
|
||||
-- 查询男女学生的人数(分组和聚合函数)
|
||||
select if(stusex, '男', '女') as `性别`, count(stusex) as `人数` from TbStudent group by stusex;
|
||||
|
||||
-- 查询课程编号为1111的课程的平均成绩(筛选和聚合函数)
|
||||
select avg(score) as `平均成绩` from TbSC where cid=1111;
|
||||
select if(stusex, '男', '女') as 性别, count(stusex) as 人数
|
||||
from tb_student group by stusex order by 人数 desc;
|
||||
|
||||
-- 查询学号为1001的学生所有课程的总成绩(筛选和聚合函数)
|
||||
select sum(score) as `总成绩` from TbSC where sid=1001;
|
||||
select sum(score) as 总成绩 from tb_score where sid=1001;
|
||||
|
||||
-- 查询每个学生的学号和平均成绩, null值处理成0(分组和聚合函数)
|
||||
select sid as `学号`, ifnull(avg(score), 0) as `平均成绩` from TbSC group by sid;
|
||||
-- 查询每个学生的学号和平均成绩(分组和聚合函数)
|
||||
select sid as 学号, avg(score) as 平均分
|
||||
from tb_score
|
||||
where score is not null
|
||||
group by sid
|
||||
order by 平均分 desc;
|
||||
|
||||
-- 查询平均成绩大于等于90分的学生的学号和平均成绩
|
||||
select sid as `学号`, avg(score) as `平均成绩` from TbSC group by sid having avg(score)>=90;
|
||||
-- 查询平均成绩大于等于80分的学生的学号和平均成绩(分组后的筛选)
|
||||
select sid as 学号, avg(score) as 平均分
|
||||
from tb_score
|
||||
group by sid having 平均分>=80
|
||||
order by 平均分 desc;
|
||||
|
||||
-- 查询年龄最大的学生的姓名(子查询)
|
||||
select stuname from TbStudent where stubirth=(select min(stubirth) from TbStudent);
|
||||
select stuname from tb_student
|
||||
where stubirth=(select min(stubirth) from tb_student);
|
||||
select stuname from tb_student
|
||||
where stubirth=(select max(stubirth) from tb_student);
|
||||
|
||||
-- 查询选了三门及以上的课程的学生姓名(子查询/分组条件/集合运算)
|
||||
select stuname from tb_student where stuid in
|
||||
(select sid from tb_score group by sid having count(sid)>=3);
|
||||
|
||||
-- 查询课程名称、学分、授课老师的名字和职称
|
||||
select cname, ccredit, tname, ttitle
|
||||
from tb_course, tb_teacher
|
||||
where tid=teacherid;
|
||||
|
||||
select cname, ccredit, tname, ttitle
|
||||
from tb_course inner join tb_teacher
|
||||
on tid=teacherid;
|
||||
|
||||
-- 查询学生姓名和所在学院名称
|
||||
select stuname, collname
|
||||
from tb_student t1, tb_college t2
|
||||
where t1.collid=t2.collid;
|
||||
|
||||
select stuname, collname from tb_student t1
|
||||
inner join tb_college t2 on t1.collid=t2.collid;
|
||||
|
||||
-- 查询学生姓名、课程名称以及考试成绩
|
||||
|
||||
-- 查询选了两门以上的课程的学生姓名(子查询/分组条件/集合运算)
|
||||
select stuname from TbStudent where stuid in
|
||||
(select sid from TbSC group by sid having count(sid)>2);
|
||||
|
||||
-- 查询选课学生的姓名和平均成绩(子查询和连接查询)
|
||||
-- 写法1:
|
||||
select stuname, avgscore from TbStudent t1 inner join
|
||||
(select sid, avg(score) as avgscore from TbSC where score is not null group by sid) t2 on t1.stuid=t2.sid;
|
||||
-- 写法2:
|
||||
select stuname, avgscore from TbStudent t1,
|
||||
(select sid, avg(score) as avgscore from TbSC where score is not null group by sid) t2 where t1.stuid=t2.sid;
|
||||
|
||||
|
||||
-- 查询学生姓名、所选课程名称和成绩(连接查询)
|
||||
-- 写法1:
|
||||
select stuname, cosname, score from
|
||||
TbStudent t1, TbCourse t2, TbSC t3
|
||||
where t1.stuid=t3.sid and t2.cosid=t3.cid and t3.score is not null;
|
||||
-- 写法2:
|
||||
select stuname, cosname, score from TbStudent t1 inner join TbCourse t2
|
||||
inner join (select sid, cid, score from TbSC where score is not null) t3
|
||||
on t1.stuid=t3.sid and t2.cosid=t3.cid;
|
||||
|
||||
|
||||
-- 查询每个学生的姓名和选课数量(左外连接和子查询)
|
||||
select stuname as `姓名`, ifnull(coscount, 0) as `选课数` from TbStudent t1
|
||||
left outer join (select sid, count(sid) as coscount from TbSC group by sid) t2 on t1.stuid=t2.sid;
|
||||
|
||||
```
|
||||
|
||||
4. DCL
|
||||
|
|
@ -248,6 +319,22 @@
|
|||
revoke insert, delete, update on SRS.* from 'hellokitty'@'localhost';
|
||||
```
|
||||
|
||||
### 相关知识
|
||||
|
||||
#### 范式理论
|
||||
|
||||
#### 数据完整性
|
||||
|
||||
1. 实体完整性 - 每个实体都是独一无二的
|
||||
- 主键 / 唯一约束 / 唯一索引
|
||||
2. 引用完整性（参照完整性）
|
||||
- 外键
|
||||
3. 域完整性 - 数据是有效的
|
||||
- 数据类型
|
||||
- 非空约束
|
||||
- 默认值约束
|
||||
- 检查约束
|
||||
|
||||
### Python数据库编程
|
||||
|
||||
1. MySQLdb
|
||||
|
|
|
|||
Loading…
Reference in New Issue