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This article mainly explains "how to understand Oracle Tablespace". The explanation in this article is simple and clear, easy to learn and understand. Please follow the ideas of Xiaobian slowly and deeply to study and learn "how to understand Oracle Tablespace" together!

1. Query all current tablespaces

SQL> select tablespace_name from dba_tablespaces;

TABLESPACE_NAME

------------------------------

SYSTEM

SYSAUX

UNDOTBS1

TEMP

USERS

EXAMPLE

2. Query the current data file

SQL> select file_name,tablespace_name from dba_data_files;

FILE_NAME TABLESPACE_NAME

-------------------------------------------------- ------------------------------

/u01/app/oracle/oradata/orcl/users01.dbf USERS

/u01/app/oracle/oradata/orcl/undotbs01.dbf UNDOTBS1

/u01/app/oracle/oradata/orcl/sysaux01.dbf SYSAUX

/u01/app/oracle/oradata/orcl/system01.dbf SYSTEM

/u01/app/oracle/oradata/orcl/example01.dbf EXAMPLE

3. Various tablespaces

1) System table space

Oracle data dictionary information is stored, reflecting Oracle system information.

(2) Sysaux Tablespace

Is a secondary table space to the system table space that holds unimportant system information.

System and sysaux tablespaces must be online at the same time, otherwise the database will not get up.

(3) undo table space

Undo table space is the system table space, the information stored in it is, each time the user changes the data block, Oracle will change the information block into the undo table space.

(4) temp table space

Temporary tablespaces, where temporary data is stored. When adding, deleting, and searching, temp tablespaces are temporarily used when memory space is insufficient.

System/sysaux/undo/temp are all system-level tablespaces.

(5) Example Tablespace

Example tablespaces store sample databases, usually scott user databases, for practice.

(6) Users Tablespace

Tablespace used to store user data. User data is placed under the users table space unless another user table space is created.

In a normal production system, these two tablespaces are absent. Even if there were, they wouldn't be needed!

(7) Autoextend option

When creating a tablespace specified data file, there is an autoextend option, meaning automatic extension. When the data file is full, it will automatically expand. However, in a production environment, you specify the autoextend option, and when the data file usage is>85%, you still use the alter tablespace name add datafile format 'path' command to create a new tablespace.

Thank you for reading, the above is "how to understand Oracle tablespaces" content, after the study of this article, I believe you have a deeper understanding of how to understand Oracle tablespaces this problem, the specific use of the situation also needs to be verified by practice. Here is, Xiaobian will push more articles related to knowledge points for everyone, welcome to pay attention!

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