1. # mongodb安装
    2. brew tap mongodb/brew
    3. sudo brew install mongodb-community@4.2
    4. # 服务开启
    5. brew services start mongodb-community@4.2
    6. # 查看mongodb是否安装成功
    7. mongod --version
    8. # 创建表
    9. use pule_decision
    10. db.test.insert({'name': 'ksir'})
    11. show dbs