dba_tables 的最后更新时间问题

Question

select last_dll_time from dba_tables 
在oracle里这张系统表里的last_dll_time难道不是表的最近更新时间么？

Answer 1

是表的最后修改时间，包括
1.When DDL is performed on the dependent objects of the table.
For example when an index is created or altered.2.When a table is truncated3.When roles/privileges are granted/revoked.

Answer 2

用语句：analyze table table_name computer statistics就可以了，那么相应的信息在数据字典中就会发生变化了

Answer 3

最后的一个有关表的ddl语句作用的时间

Answer 4

select last_dll_time from dba_tables dba_tables有这个字段吗？SQL> desc all_objects
Name           Type         Nullable Default Comments                                                                     
-------------- ------------ -------- ------- ---------------------------------------------------------------------------- 
OWNER          VARCHAR2(30)                  Username of the owner of the object                                          
OBJECT_NAME    VARCHAR2(30)                  Name of the object                                                           
SUBOBJECT_NAME VARCHAR2(30) Y                Name of the sub-object (for example, partititon)                             
OBJECT_ID      NUMBER                        Object number of the object                                                  
DATA_OBJECT_ID NUMBER       Y                Object number of the segment which contains the object                       
OBJECT_TYPE    VARCHAR2(19) Y                Type of the object                                                           
CREATED        DATE                          Timestamp for the creation of the object                                     
LAST_DDL_TIME  DATE                          Timestamp for the last DDL change (including GRANT and REVOKE) to the object 
TIMESTAMP      VARCHAR2(19) Y                Timestamp for the specification of the object                                
STATUS         VARCHAR2(7)  Y                Status of the object                                                         
TEMPORARY      VARCHAR2(1)  Y                Can the current session only see data that it placed in this object itself?  
GENERATED      VARCHAR2(1)  Y                Was the name of this object system generated?                                
SECONDARY      VARCHAR2(1)  Y                Is this a secondary object created as part of icreate for domain indexes?    

Answer 5

SQL> desc dba_tables                                                                                
 Name                                                              Null?    Type
 ----------------------------------------------------------------- -------- --------------------------------------------
 OWNER                                                             NOT NULL VARCHAR2(30)
 TABLE_NAME                                                        NOT NULL VARCHAR2(30)
 TABLESPACE_NAME                                                            VARCHAR2(30)
 CLUSTER_NAME                                                               VARCHAR2(30)
 IOT_NAME                                                                   VARCHAR2(30)
 STATUS                                                                     VARCHAR2(8)
 PCT_FREE                                                                   NUMBER
 PCT_USED                                                                   NUMBER
 INI_TRANS                                                                  NUMBER
 MAX_TRANS                                                                  NUMBER
 INITIAL_EXTENT                                                             NUMBER
 NEXT_EXTENT                                                                NUMBER
 MIN_EXTENTS                                                                NUMBER
 MAX_EXTENTS                                                                NUMBER
 PCT_INCREASE                                                               NUMBER
 FREELISTS                                                                  NUMBER
 FREELIST_GROUPS                                                            NUMBER
 LOGGING                                                                    VARCHAR2(3)
 BACKED_UP                                                                  VARCHAR2(1)
 NUM_ROWS                                                                   NUMBER
 BLOCKS                                                                     NUMBER
 EMPTY_BLOCKS                                                               NUMBER
 AVG_SPACE                                                                  NUMBER
 CHAIN_CNT                                                                  NUMBER
 AVG_ROW_LEN                                                                NUMBER
 AVG_SPACE_FREELIST_BLOCKS                                                  NUMBER
 NUM_FREELIST_BLOCKS                                                        NUMBER
 DEGREE                                                                     VARCHAR2(10)
 INSTANCES                                                                  VARCHAR2(10)
 CACHE                                                                      VARCHAR2(5)
 TABLE_LOCK                                                                 VARCHAR2(8)
 SAMPLE_SIZE                                                                NUMBER
 LAST_ANALYZED                                                              DATE
 PARTITIONED                                                                VARCHAR2(3)
 IOT_TYPE                                                                   VARCHAR2(12)
 TEMPORARY                                                                  VARCHAR2(1)
 SECONDARY                                                                  VARCHAR2(1)
 NESTED                                                                     VARCHAR2(3)
 BUFFER_POOL                                                                VARCHAR2(7)
 ROW_MOVEMENT                                                               VARCHAR2(8)
 GLOBAL_STATS                                                               VARCHAR2(3)
 USER_STATS                                                                 VARCHAR2(3)
 DURATION                                                                   VARCHAR2(15)
 SKIP_CORRUPT                                                               VARCHAR2(8)
 MONITORING                                                                 VARCHAR2(3)
 CLUSTER_OWNER                                                              VARCHAR2(30)
 DEPENDENCIES                                                               VARCHAR2(8)
 COMPRESSION                                                                VARCHAR2(8)
 DROPPED                                                                    VARCHAR2(3)SQL> desc dba_objects                                                                               
 Name                                                              Null?    Type
 ----------------------------------------------------------------- -------- --------------------------------------------
 OWNER                                                                      VARCHAR2(30)
 OBJECT_NAME                                                                VARCHAR2(128)
 SUBOBJECT_NAME                                                             VARCHAR2(30)
 OBJECT_ID                                                                  NUMBER
 DATA_OBJECT_ID                                                             NUMBER
 OBJECT_TYPE                                                                VARCHAR2(19)
 CREATED                                                                    DATE
 LAST_DDL_TIME                                                              DATE
 TIMESTAMP                                                                  VARCHAR2(19)
 STATUS                                                                     VARCHAR2(7)
 TEMPORARY                                                                  VARCHAR2(1)
 GENERATED                                                                  VARCHAR2(1)
 SECONDARY                                                                  VARCHAR2(1)可能版本不一样吧

Answer 6

最后DDL语句。。也就是对表结构操作