怎样在CentOS上从零开始安装数据库

以下是在CentOS上从零开始安装数据库的步骤，以MySQL和PostgreSQL为例：

安装MySQL

1. 更新系统：sudo yum update -y
2. 添加MySQL官方YUM仓库：sudo wget https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm，sudo rpm -Uvh mysql80-community-release-el7-3.noarch.rpm
3. 安装MySQL服务器：sudo yum install mysql-server -y
4. 启动MySQL服务并设置开机自启：sudo systemctl start mysqld，sudo systemctl enable mysqld
5. 获取临时密码：sudo grep 'temporary password' /var/log/mysqld.log
6. 运行安全脚本：sudo mysql_secure_installation，按提示设置新密码等
7. 登录MySQL：mysql -u root -p

安装PostgreSQL

1. 更新系统：sudo yum update -y
2. 添加PostgreSQL官方YUM仓库：sudo yum install -y https://download.postgresql.org/pub/repos/yum/reporpms/EL-$(rpm -E %{rhel})-x86_64/pgdg-redhat-repo-latest.noarch.rpm
3. 禁用CentOS自带PostgreSQL模块：sudo dnf -qy module disable postgresql
4. 安装PostgreSQL：sudo yum install -y postgresql-server postgresql-contrib
5. 初始化数据库：sudo /usr/pgsql-版本号/bin/postgresql-setup initdb
6. 启动PostgreSQL服务并设置开机自启：sudo systemctl start postgresql，sudo systemctl enable postgresql
7. 设置PostgreSQL超级用户密码：sudo -i -u postgres，psql，ALTER USER postgres PASSWORD 'your_password';，\q