1.虚拟机和Ubuntu系统安装

虚拟机永久激活密钥：YZ718-4REEQ-08DHQ-JNYQC-ZQRD0

由于官网服务器在国外，下载速度奇慢，所以我们可以利用阿里云镜像下载ubuntu
ubuntu 14.04：
http://mirrors.aliyun.com/ubuntu-releases/14.04/
ubuntu 16.04：
http://mirrors.aliyun.com/ubuntu-releases/16.04/
ubuntu 18.04：
http://mirrors.aliyun.com/ubuntu-releases/18.04/
没错，只要市面上存在的版本，阿里云镜像基本都有，下载速度可以达到3M/s
转

2.安装环境

2.1：首先检测是否安装了build-essential程序包

sudo apt-get install build-essential

2.2

sudo apt-get  install yum


sudo apt-get install java-1.7.0*

2.3 Readline库的安装

在Ubuntu下命令行安装
sudo apt-get install libreadline6-dev

2.4 zlib库的安装

在Ubuntu下命令行安装
命令行方式：
sudo apt-get install zlib1g-dev

2.5 flex bison库的安装

在Ubuntu下命令行安装
Ubuntu下使用sudo apt-get install flex bison命令

3.postgre

cd /home/xpb/Documents/postgresql

/home/xpb/Documents/bin/initdb -D ~/pgdata
/usr/bin/initdb -D ~/pgdata
cd /usr/bin/initdb
./configure --prefix=/home/xpb/Documents --enable-depend --enable-cassert --enable-debug
tar -zxvf postgresql-9.6.9.tar.gz

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Success. You can now start the database server using:

./bin/pg_ctl -D /home/xpb/pgdata -l logfile start

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箭头指向的参数要是上一句编译成功之后语句里的参数： -D /home/xpb/pgdata
cd /home/xpb/Documents
./bin/pg_ctl -D /home/xpb/pgdata -l logfile start

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export LD_LIBRARY_PATH=/home/xpb/Documents/postgresql/lib
vi /home/xpb/.bashrc

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3.数据库创建

#创建新的数据库
CREATE DATABASE school OWNER xpb;
## 登录数据库
$ psql -U xpb -d school
## 列举数据库
\l
#切换数据库
\c  school

create table class (classno int,classname varchar(50), gno varchar(20));
create table student(sno int, sname varchar(50), sex varchar(20), age int, nation varchar(50), classno int);
create table course(cno int, cname varchar(50), credit int);
create table sc(sno int, cno int, score int);


#添加数据
insert into class values (0, '2017', '2017'),   (1, '2018','2018'), (2, '2019', '2019');

insert into student values (0,'ding','nan',18,'china',0),(1,'xiang','nan',18,'china',0),(2,'guo','nan',18,'china',1);

insert into course values(0, 'math', 0),   (1, 'english', 0), (2, 'chinese', 0);

insert into sc values(0, 0,100), (1,0,100), (0,1,100);

#查询实例语句
select classno,classname
from sc, class,course
where sc.sno in (select sno from student where student.classno =class.classno)
and sc.cno = course.cno
and course.cname = 'math'
and class.gno = '2017'