sqlplus命令行启动关闭oracle数据库

           oracle数据的启动和关闭

            一，启动oracle数据库的三个步骤   1.启动实例   2.加载数据库  3.打开数据库 

          启动oracle数据库命令    1.startup   2.startup  nomount   3.startup  mount

                                启动实例 ，不加载数据库                       加载数据库                          打开数据库       

         startup                        是                                                         是                                          是

     startup nomount          是                                                         否                                           否

     startup    mount            是                                                        是                                            否

startup  相当于  ：

                               startup nomount                       启动实例

                               alter  database mount             加载数据库

                                alter  database    open           打开数据库

二，关闭oracle数据库    shutdown    mode

       1.shutdown  abort      2.shutdown  immediate    3.shutdown transactional   4 shutdown  normal

         shutdown  mode                                           Abort                  Immediate          transactional          normal                   

   allow new connections                                        no                         no                          no                           no   

 wait  until  current sessions end                        no                          no                           no                           yes

wait   until  current  transactions  end                 no                         no                           yes                         yes

force  a  checkpoint  and  close files                  no                         yes                          yes                          yes