oracle 所有查询和表空间，以及其关系，oracle空间
select * from dba_users; 查看数据库里面所有用户，前提是你是有dba权限的帐号，如sys,system
select * from all_users; 查看你能管理的所有用户
select * from user_users; 查看当前用户信息
查询用户的表空间：
select username,default_tablespace from dba_users; 查询数据库所有用户所在表空间
select username,default_tablespace from user_users; 产线当前用户所在表空间
查询所有表空间名称：
select tablespace_name from dba_tablespaces;
很简单，查 dba_tablespaces 数据字典：
select tablespace_name from dba_tablespaces;
系统数据字典 DBA_TABLESPACES 中记录了关于表空间的详细信息：
select * from sys.dba_tablespaces;
数据字典 DBA_TABLESPACES 中的字段和含义:
TABLESPACE_NAME
Tablespace name
BLOCK_SIZE
Tablespace block size
INITIAL_EXTENT
Default initial extent size
NEXT_EXTENT
Default incremental extent size
MIN_EXTENTS
Default minimum number of extents
MAX_EXTENTS
Default maximum number of extents
PCT_INCREASE
Default percent increase for extent size
MIN_EXTLEN
Minimum extent size for the tablespace
STATUS
"Tablespace status: "ONLINE","OFFLINE" or "READ
CONTENTS
Tablespace contents: "PERMANENT" or "TEMPORARY" or "UNDO"
LOGGING
Default logging attribute
FORCE_LOGGING
Tablespace force logging mode
EXTENT_MANAGEMENT
Extent management tracking: "DICTIONARY" or "LOCAL"
ALLOCATION_TYPE
Type of extent allocation in effect for this tablespace
PLUGGED_IN
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SEGMENT_SPACE_MANAGEMENT
Segment space management tracking: "AUTO" or "MANUAL"