About Tablespaces

A database is divided into logical storage units called tablespaces, which group related logical structures (such as tables, views, and other database objects). For example, all application objects can be grouped into a single tablespace to simplify maintenance operations.

A tablespace consists of one or more physical data files. Database objects assigned to a tablespace are stored in the physical data files of that tablespace.

When you create an Oracle database, some tablespaces already exist, such as SYSTEM and SYSAUX.

Tablespaces provide a means to physically locate data on storage. When you define the data files that comprise a tablespace, you specify a storage location for these files. For example, you might specify a data file location for a certain tablespace as a designated host directory (implying a certain disk volume) or designated Oracle Automatic Storage Management disk group. Any schema objects assigned to that tablespace then get located in the specified storage location. Tablespaces also provide a unit of backup and recovery. The backup and recovery features of Oracle Database enable you to back up or recover at the tablespace level.

Table 6-1 describes some tablespaces included in the database.

Table 6-1 Tablespaces and Descriptions

Tablespace	Description
`EXAMPLE`	This tablespace contains the sample schemas that are included with Oracle Database. The sample schemas provide a common platform for examples. Oracle documentation and educational materials contain examples based on the sample schemas.
`SYSTEM`	This tablespace is automatically created at database creation. Oracle Database uses it to manage the database. It contains the data dictionary, which is the central set of tables and views used as a read-only reference for a particular database. It also contains various tables and views that contain administrative information about the database. These are all contained in the `SYS` schema, and can be accessed only by the `SYS` user or other administrative users with the required privilege.
`SYSAUX`	This is an auxiliary tablespace to the `SYSTEM` tablespace. The `SYSAUX` tablespace contains data for some components and products, reducing the load on the `SYSTEM` tablespace. Every database using Oracle Database 10g release 1 (10.1) or later must have a `SYSAUX` tablespace. Components that use `SYSAUX` as their default tablespace during installation include Automatic Workload Repository, Oracle Streams, and Oracle Text. For more information, see Oracle Database Administrator's Guide.
`TEMP`	This tablespace stores temporary data generated when processing SQL statements. For example, this tablespace would be used for query sorting. Every database should have a temporary tablespace that is assigned to users as their temporary tablespace. In the preconfigured database, the `TEMP` tablespace is specified as the default temporary tablespace. If no temporary tablespace is specified when a user account is created, then Oracle Database assigns this tablespace to the user.
`UNDOTBS1`	This is the undo tablespace used by the database to store undo information. See "Managing Undo Data" to understand how an Oracle database uses the undo tablespace. Every database must have an undo tablespace.
`USERS`	This tablespace is used to store permanent user objects and data. Similar to the `TEMP` tablespace, every database should have a tablespace for permanent user data that is assigned to users. Otherwise, user objects will be created in the `SYSTEM` tablespace, which is not good practice. In the preconfigured database, `USERS` is designated as the default tablespace for all new users.

You can create new tablespaces to support your user and application data requirements. During tablespace creation, you set the following parameters: