Tham khảo tài liệu 'oracle database 10g the complete reference phần 4', công nghệ thông tin, cơ sở dữ liệu phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 388 Part III Beyond the Basics The read-only status for tablespaces is displayed via the Status column of the USER TABLESPACES data dictionary view as shown in the following example alter tablespace USERS read only Tablespace altered. select Status from USER_TABLESPACES where Tablespace_Name USERS STATUS READ ONLY alter tablespace USERS read write Tablespace altered. select Status from USER_TABLESPACES where Tablespace_Name USERS STATUS ONLINE nologging Tablespaces You can disable the creation of redo log entries for specific objects. By default Oracle generates log entries for all transactions. If you wish to bypass that functionality for instance if you are loading data and you can completely re-create all the transactions you can specify that the loaded object or the tablespace be maintained in nologging mode. You can see the current logging status for tablespaces by querying the Logging column of USER_TABLESPACES. Temporary Tablespaces When you execute a command that performs a sorting or grouping operation Oracle may create a temporary segment to manage the data. The temporary segment is created in a temporary tablespace and the user executing the command does not have to manage that data. Oracle will dynamically create the temporary segment and will release its space when the instance is shut down and restarted. If there is not enough temporary space available and the temporary tablespace datafiles cannot autoextend the command will fail. Each user in the database has an associated temporary tablespace there may be just one such tablespace for all users to share. A default temporary tablespace is set at the database level so all new users will have the same temporary tablespace unless a different one is specified during the create user or alter user command. As of Oracle Database 10g you can create multiple temporary tablespaces and group them. Assign the temporary tablespaces to tablespace groups via the tablespace group clause of the create temporary .
