谁能说说user_tables中的各项的意思吗?

OWNER VARCHAR2 ( 30 ) NOT NULL Owner of the table

TABLE_NAME VARCHAR2
( 30 ) NOT NULL Name of the table

TABLESPACE_NAME VARCHAR2
( 30 )

Name of the tablespace containing the table ; null for partitioned , temporary , and index - organized tables

CLUSTER_NAME VARCHAR2
( 30 )

Name of the cluster , if any , to which the table belongs

IOT_NAME VARCHAR2
( 30 )

Name of the index - organized table , if any , to which the overflow or mapping table entry belongs . If the IOT_TYPE column is not null , then this column contains the base table name .
STATUS VARCHAR2 ( 8 ) If a previous DROP TABLE operation failed , indicates whether the table is unusable ( UNUSABLE ) or valid ( VALID )
PCT_FREE NUMBER

Minimum percentage of free space in a block
; null for partitioned tables

PCT_USED NUMBER

Minimum percentage of used space in a block
; null for partitioned tables

INI_TRANS NUMBER

Initial number of transactions
; null for partitioned tables

MAX_TRANS NUMBER

Maximum number of transactions
; null for partitioned tables

INITIAL_EXTENT NUMBER

Size of the initial extent
( in bytes ); null for partitioned tables

NEXT_EXTENT NUMBER

Size of secondary extents
( in bytes ); null for partitioned tables

MIN_EXTENTS NUMBER

Minimum number of extents allowed in the segment
; null for partitioned tables

MAX_EXTENTS NUMBER

Maximum number of extents allowed in the segment
; null for partitioned tables

PCT_INCREASE NUMBER

Percentage increase in extent size
; null for partitioned tables

FREELISTS NUMBER

Number of process freelists allocated to the segment
; null for partitioned tables

FREELIST_GROUPS NUMBER

Number of freelist groups allocated to the segment
; null for partitioned tables

LOGGING VARCHAR2
( 3 )

Logging attribute ; NULL for partitioned tables

BACKED_UP VARCHAR2
( 1 )

Has table been backed up since last change

NUM_ROWS
* NUMBER

Number of rows in the table

BLOCKS
* NUMBER

Number of used data blocks in the table

EMPTY_BLOCKS
* NUMBER

Number of
empty ( never used ) data blocks in the table

AVG_SPACE
* NUMBER

Average amount of free space
, in bytes , in a data block allocated to the table

CHAIN_CNT
* NUMBER

Number of rows in the table that are chained from one data block to another
, or which have migrated to a new block , requiring a link to preserve the old ROWID

AVG_ROW_LEN
* NUMBER

Average length of a row in the table
( in bytes )
AVG_SPACE_FREELIST _BLOCKS NUMBER

Average freespace of all blocks on a freelist

NUM_FREELIST_BLOCKS NUMBER

Number of blocks on the freelist

DEGREE VARCHAR2
( 10 )

Number of threads per instance for scanning the table

INSTANCES VARCHAR2
( 10 )

Number of instances across which the table is to be scanned

CACHE VARCHAR2
( 5 )

Indicates whether the table is to be cached in the buffer cache ( Y ) or not ( N )
TABLE_LOCK VARCHAR2 ( 8 )

Indicates whether table locking is enabled ( ENABLED ) or disabled ( DISABLED )
SAMPLE_SIZE NUMBER

Sample size used in analyzing this table

LAST_ANALYZED DATE

Date on which this table was most recently analyzed

PARTITIONED VARCHAR2
( 3 )

Indicates whether this table is partitioned . Set to YES if it is partitioned .
IOT_TYPE VARCHAR2 ( 12 )

If
this is an index - organized table , then IOT_TYPE is IOT , IOT_OVERFLOW , or IOT_MAPPING . If this is not an index - organized table , then IOT_TYPE is NULL .
TEMPORARY VARCHAR2 ( 1 )

Can the current session only see data that it place in this object itself ?
SECONDARY VARCHAR2 ( 1 )

Whether the trigger is a secondary object created by the ODCIIndexCreate method of the Oracle Data Cartridge ( Y | N )
NESTED VARCHAR2 ( 3 )

Indicates whether the table is a nested table ( YES ) or not ( NO )
BUFFER_POOL VARCHAR2 ( 7 )

The default buffer pool for the object . NULL for partitioned tables

ROW_MOVEMENT VARCHAR2
( 8 )

Whether partitioned row movement is enabled or disabled

GLOBAL_STATS VARCHAR2
( 3 )

For
partitioned tables , indicates whether statistics were collected for the table as a whole ( YES ) or were estimated from statistics on underlying partitions and subpartitions ( NO )
USER_STATS VARCHAR2 ( 3 )

Indicates whether statistics were entered directly by the user ( YES ) or not ( NO )
DURATION VARCHAR2 ( 15 )

Indicates the duration of a temporary table :
SYS$SESSION : the rows are preserved for the duration of the session



SYS$TRANSACTION
: the rows are deleted after COMMIT



Null
for a permanent table



SKIP_CORRUPT VARCHAR2
( 8 )

Whether the Oracle Database ignores blocks marked corrupt during table and index scans ( ENABLED ) or raises an error ( DISABLED ). To enable this feature , run the DBMS_REPAIR . SKIP_CORRUPT_BLOCKS procedure .
MONITORING VARCHAR2 ( 3 )

Whether the table has the MONITORING attribute set

CLUSTER_OWNER VARCHAR2
( 30 ) Owner of the cluster , if any , to which the table belongs

DEPENDENCIES VARCHAR2
( 8 ) Indicates whether row - level dependency tracking is enabled ( ENABLED ) or disabled ( DISABLED )
COMPRESSION VARCHAR2 ( 8 ) Indicates whether table compression is enabled ( ENABLED ) or not ( DISABLED ); null for partitioned tables

DROPPED VARCHAR2
( 3 ) Indicates whether the table has been dropped and is in the recycle bin ( YES ) or not ( NO ); null for partitioned tables




来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/92530/viewspace-128004/,如需转载,请注明出处,否则将追究法律责任。

转载于:http://blog.itpub.net/92530/viewspace-128004/

你可能感兴趣的:(谁能说说user_tables中的各项的意思吗?)