Detailed description of switch and restricted status and read-only status between Oracle startup Modes

Use the Alter Database statement to switch between startup modes.
1. switch from NoMount mode to Mount mode (not from mount to nomount): Command: alter database mount; 2. when the DATABASE status is closed, switch to the Open mode command: alter database open; www.2cto.com 3. in Open mode, you can also set the database to a non-restricted or restricted State. Command: When enabling Open mode, add the restrict Keyword: startup restrict setting or canceling the restricted State: alter system enable \ disable restricted session; Explanation: unrestricted state, it is the status that we usually use for application development. Restricted status. When the opened database is set to Restricted, only the Create Session and Restricted Session system permissions or users with SYSDBA and SYSPORE system permissions can connect to the database. However, after entering the restricted State, there may still be active common user sessions in the system. Restricted state purpose: (1) perform data import or export operations; (2) temporarily refuse normal users to access the database; www.2cto.com (3) port the database or upgrade the database. 4. read-only status setting command: alter database open read only; cancel read-only command: alter database open read write; purpose & Description: When a normally opened database is set to read-only, you can only query data, but cannot modify database objects in any way. In the read-only status, the content in the data file and the redo log file may not be modified, but it does not limit the operations that do not write data files or redo log files. Author lutinghuan