How a Database Is Mounted (293)

The instance mounts a database to associate the database with that instance. To mount
the database, the instance finds the database control files and opens them. Control files
are specified in the CONTROL_FILES initialization parameter in the parameter file
used to start the instance. Oracle then reads the control files to get the names of the
database’s datafiles and redo log files.

At this point, the database is still closed and is accessible only to the database
administrator. The database administrator can keep the database closed while
completing specific maintenance operations. However, the database is not yet
available for normal operations.

裝載資料庫
1. 在掛載資料庫時,例項首先需要找到並開啟資料庫控制檔案(CONTROL_FILES),
接著 Oracle 將讀取控制檔案獲取資料庫的資料檔名及重做日誌檔名。
2. 這個時候資料庫還沒有開啟, 只有DBA才能訪問資料庫

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