Note:
The DICTIONARY keyword is deprecated. It is still supported for backward compatibility. However, Oracle recommends that you create locally managed tablespaces. Locally managed tablespaces are much more efficiently managed than dictionary-managed tablespaces. The creation of new dictionary-managed tablespaces is scheduled for desupport.
根据表空间中区的管理方式不周，表空间可以分为数据字典管理（Dictionary managed）与本地化管理（Local Managed）类型。
在数据字典管理表空间中，区大小由参数：
initial, next, minextents, maxextents, pctincrease 决定。
在本地化管理中，区大小设置方式分为uniform 及autoallocate 两种类型。
Uniform：区的大小相同。如果设置了uniform 则pctincrease 自动为0。
Autoallocate：区大小oracle自动分配。
Oracle9i之前的，通常是数据字典管理。Oracle9i及以后，通常使用本地化管理表空间。
Use the BLOCKSIZE clause to specify a nonstandard block size for the tablespace. In order to specify this clause, the DB_CACHE_SIZE and at least one DB_nK_CACHE_SIZE parameter must be set, and the integer you specify in this clause must correspond with the setting of one DB_nK_CACHE_SIZE parameter setting.
Restriction on BLOCKSIZE You cannot specify nonstandard block sizes for a temporary tablespace or if you intend to assign this tablespace as the temporary tablespace for any users.
The segment_management_clause is relevant only for permanent, locally managed tablespaces. It lets you specify whether Oracle Database should track the used and free space in the segments in the tablespace using free lists or bitmaps. This clause is not valid for a temporary tablespace.
Specify AUTO if you want the database to manage the free space of segments in the tablespace using a bitmap. If you specify AUTO, then the database ignores any specification for PCTUSED, FREELIST, and FREELIST GROUPS in subsequent storage specifications for objects in this tablespace. This setting is called automatic segment-space management and is the default.
Specify MANUAL if you want the database to manage the free space of segments in the tablespace using free lists. Oracle strongly recommends that you do not use this setting and that you create tablespaces with automatic segment-space management.
To determine the segment management of an existing tablespace, query the SEGMENT_SPACE_MANAGEMENT column of the DBA_TABLESPACES or USER_TABLESPACES data dictionary view.
Notes:
If you specify AUTO segment management, then:
（1）. If you set extent management to LOCAL UNIFORM, then you must ensure that each extent contains at least 5 database blocks.
（2）. If you set extent management to LOCAL AUTOALLOCATE, and if the database block size is 16K or greater, then Oracle manages segment space by creating extents with a minimum size of 5 blocks rounded up to 64K.
Restrictions on Automatic Segment-Space Management This clause is subject to the following restrictions:
（1）. You can specify this clause only for a permanent, locally managed tablespace.
（2）. You cannot specify this clause for the SYSTEM tablespace.
Use this clause in conjunction with the ALTER DATABASE FLASHBACK clause to specify whether the tablespace can participate in FLASHBACK DATABASE operations. This clause is useful if you have the database in FLASHBACK mode but you do not want Oracle Database to maintain Flashback log data for this tablespace.
This clause is not valid for tem