Oracle tablespace creation syntax

Tablespace is an important concept in Oracle databases. The following describes the syntax for creating tablespaces in Oracle. We hope that you can have a better understanding of creating tablespaces in Oracle.

Syntax description for creating a tablespace in Oracle:

CREATE [UNDO] TABLESPACE tablespace_name

[DATAFILE datefile_spec1 [, datefile_spec2] ......

[{Mininum extent integer [k | m]

| BLOCKSIZE integer [k]

| Logging clause

| FORCE LOGGING

| DEFAULT {data_segment_compression} storage_clause

| [Online | offline]

| [PERMANENT | TEMPORARY]

| Extent_manager_clause

| Segment_manager_clause}]

1. undo

The system creates a tablespace for rollback.

In 9i, the database administrator can manage rollback segments without having to create undo tablespaces. The system automatically manages rollback segment allocation and recovery. Of course, you can also create a general tablespace and create a rollback segment on it. however, for users, system management is much better than self-management. if you need to manage it by yourself, see the detailed command for rollback segment management.

When the system does not specify a tablespace for rollback, the system uses the system rollback segment for transaction management.

2. tablespace

Name of the tablespace.

3. datafile datefile_spec1

Specifies the space file contained in the tablespace. Datefile_spec1 is like ['filename'] [SIZE integer [K | M] [REUSE] [autoextend_clause]

[Autoextend_clause] is an example: AUTOEXTEND {OFF | ON [NEXT integer [K | M] [maxsize_clause]}

Filename indicates the full path name of the data file, size indicates the file size, and REUSE indicates whether the file is reused.

AUTOEXTEND indicates whether automatic expansion. OFF | ON indicates whether automatic expansion is disabled. NEXT indicates the size of the expansion after the data file is full.

Maxsize_clause indicates the maximum size of the data file. For example, MAXSIZE {UNLIMITED | integer [K | M]}. UNLIMITED indicates an infinite tablespace. integer indicates the maximum size of the data file.

DATAFILE 'd: \ oracle \ oradata \ IMAGEDATA01.dbf 'size 2000 M,

'D: \ oracle \ oradata \ IMAGEDATA02.dbf 'size 2000 M

4. mininum extent integer [k | m]

Specifies the minimum value of the range in the tablespace. This parameter can reduce space fragments and ensure that the range in the tablespace is an integer multiple of this value.

5. BLOCKSIZE integer [k]

This parameter can be used to set the size of an unstandard block. If you want to set this parameter, you must set db_block_size, at least one db_nk_block_size, and the declared integer value must be equal to db_nk_block_size.

Note: This parameter cannot be set in the temporary tablespace.

6. logging clause

This clause declares that the log attribute of all user objects in the tablespace is logging by default), including tables, indexes, partitions, materialized views, and indexes and partitions in materialized views.

7. FORCE LOGGING

Use this clause to indicate that the tablespace enters the forced log mode. At this time, the system records all changes to objects in the table space, except for changes to temporary segments. This parameter is higher than the object's nologging option.

Note: The database cannot be opened and is in read/write mode. This option cannot be used in temporary tablespace and rollback tablespace.

8. DEFAULT storage_clause

Declare the default storage clause.

9. online | offline

Changes the status of a tablespace. Online: The tablespace is valid immediately after being created. This is the default value. offline: Invalid after being created. This value can be obtained from dba_tablespace.

10. PERMANENT | TEMPORARY

Specifies whether a tablespace is a permanent tablespace or a temporary tablespace. Permanent tablespace stores permanent objects, while temporary tablespace stores temporary objects existing in the session lifecycle. The temporary tablespace generated by this parameter is always in dictionary management after it is created, and the extent management local option cannot be used. To create a local tablespace, you must use the create temporary tablespace

Note: block size cannot be declared after this parameter is declared.

11. extent_management_clause

This is the most important clause that describes how to manage the range of a tablespace. Once you declare this clause, you can only change these parameters by porting them.

If you want to manage the tablespace locally, declare the local option. Local tablespace management is implemented through bitmap management. Autoallocate indicates that the tablespace is automatically allocated with a range. You cannot specify the range. Only Versions later than 9.0 have this function. Uniform indicates the fixed size of the tablespace range. The default value is 1 MB.

You cannot set the system tablespace of a locally managed database to dictionary management.

Oracle recommends using local tablespace management.

If extent_management_clause is not set, oracle sets a default value for it. If the initialization parameter compatible is smaller than 9.0.0, the system creates a dictionary management tablespace. If the value is greater than 9.0.0, set the value as follows:

If default storage_clause is not specified, oracle creates an automatically assigned local tablespace.

Otherwise, if the mininum extent is specified, oracle determines whether the mininum extent, initial, and next are equal, and whether the pctincrease is = 0. if the preceding conditions are met, oracle creates a local tablespace for management, and the extent size is initial. if the preceding conditions are not met, oracle creates an automatically assigned local tablespace.

If the mininum extent is not specified. Initial, then oracle determines whether next is equal, and whether pctincrease is = 0. If you want oracle to create a local tablespace and specify the uniform. Otherwise, oracle creates an automatically allocated local tablespace.

Note: Local tablespace management can only store permanent objects. If you declare local, you cannot declare default storage_clause, mininum extent, temporary.

EXTENT MANAGEMENT LOCAL

12. segment_management_clause

SEGMENT SPACE MANAGEMENT AUTO
 
 

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