The data file is the physical storage unit of the database, while the tablespace is the logical component of the database. The database data is stored in the tablespace, and a tablespace can be composed of one or more data files. A data file can only belong to one tablespace. Once a data file is added to a tablespace, it cannot be deleted. to delete a data file, you can only delete the tablespace it belongs.
The tablespace to be generated is generally performed by DBA or privileged users. To generate a tablespace as another identity, this user must be granted the create tablespace permission. When a tablespace is generated, a data file is generally generated and the file size and segment size are determined.
Generate a tablespace to determine the data file, file size, and partition size.
Create tablespace date01 datafile D:/Oracle/oradata/scut/date01.dbf size 200 m uniform size 128 K
Delete a tablespace and data file:
Drop tablespace date01 including contents and datafiles;
Change the size of a tablespace:
? Add a data file:
Alter tablespace date01 add datafile D:/Oracle/oradata/scut/date03.dbf size 50 m;
? Manually add File Size
Alter database datafile D:/Oracle/oradata/scut/date03.dbf resize 100 m;
? Set automatic extension of file data
Alter database datafile D:/Oracle/oradata/scut/date03.dbf autoextend on next 10 m maxsize 500 m;
Move data files:
There are two ways to move data files: Alter tablespace and alter database.
? Move data files in the open state
In this state, the alter DataSpace command is used to move a file and the tablespace is required to be offline. Because system and undo tablespaces cannot be offline, they cannot be moved in this way.
The following describes how to move a common data file:
? Determine the tablespace in which the file is located:
Select tablespace_name from dba_data_files where file_name = D:/Oracle/oradata/date03.dbf;
? Take the tablespace offline:
Alter tablespace date01 offline;
? Use the OS command to move files:
Host move D:/Oracle/oradata/scut/date03.dbf D:/Oracle/ora92/date03.dbf;
? Run the alter DataSpace command to ensure that the file is moved:
Alter tablespace date01 rename datafile D:/Oracle/oradata/scut/date03.dbf to D:/Oracle/ora92/date03.dbf ';
? Bringing tablespaces online:
Alter tablespace date01 online;
? Move data files in the Mount status
In the Mount state, any data files, including system and undo tablespaces, can be moved. It uses the alter database command.
? Close Database
Shutdown immediate
Startup Mount
? Mobile Data
Host move D:/Oracle/oradata/scut/date03.dbf D:/Oracle/ora92/date03.dbf;
? Execute alter Database
Alter database date01 renam File '..... 'To '...... '
? Open Database
Alter database open
Table space, user, table relationship:
The tablespace is the container of the database logical object, and the user is the owner of the database logical object.
User -- has --> tables -- save in --> tablespace