#安装
apt install mariadb
#打开一个新窗口运行mysql服务
mysqld &
#切换回当前窗口，初始化数据库，设置密码
mariadb-secure-installation
#登录测试
mysql -uroot -p你的密码

#安装
apt install postgresql
#创建指定的数据库目录
mkdir $PREFIX/var/lib/postgresql
#初始化数据库
initdb $PREFIX/var/lib/postgresql
#启动数据库服务
pg_ctl -D $PREFIX/var/lib/postgresql -l logfile start
#启动客户端测试
psql -d postgres

yum install https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm -y

yum list | grep postgresql

yum install postgresql12-contrib postgresql12-server -y

/usr/pgsql-12/bin/postgresql-12-setup initdb

sudo systemctl start postgresql-12
sudo systemctl enable postgresql-12.service

alter user postgres with password '123456';

# 1.pg_hba.conf
vim /var/lib/pgsql/12/data/pg_hba.conf
# 文件末尾加入
host    all             all             ::1/128                 md5

# 2.postgresql.conf
# listen_addresses = 'localhost'
# 修改为listen_addresses = '*'来

CREATE DATABASE testdb;

CREATE USER testuser CREATEDB LOGIN PASSWORD 'testpassword';
将testdb所有权限赋给用户testuser
GRANT ALL ON DATABASE testdb TO testuser;

drop database testdb;

drop role testuser;