Less03_数据库体系结构.ppt

Migrate from SQL Server to Oracle Database 10g 3-* Exploring Oracle’s Database Architecture The files that constitute an Oracle database are organized into the following: Control files: Contain data about the database itself, that is, physical database structure information. These files are critical to the database. Without them, you cannot open the data files to access the data within the database. Data files: Contain the data of the database Online redo log files: Allow for instance recovery of the database. If the database crashes and does not lose any data files, then the instance can recover the database with the information in these files. Additional files, important to the successful running of the database, are: Parameter file: Used to define how the instance will be configured when it starts up Password file: Allows users to connect remotely to the database and perform administrative tasks Archive log files: Contain an ongoing history of the redo generated by the instance. These files allow for database recovery; using these files and a backup of the database, you can recover a lost data file. Migrate from SQL Server to Oracle Database 10g 3-* Exploring the Storage Structure Logical data structures are stored in the physical files of the database. You can easily view the logical structures of your database through Enterprise Manager. Detailed information about each structure can be obtained by clicking the links in the Storage region of the Administration page. Migrate from SQL Server to Oracle Database 10g 3-* Control Files When you mount and open the database instance, the control file is read. The entries in the control file specify the physical files that comprise the database. When you add additional files to your database, the control file is automatically updated. The location of the control files is specified in an initialization parameter. To protect against failure of the database due to the loss of the control file, you should multiplex t