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The main content of this article is to explain "what is the meaning of created, last_ddl_time and timestamp fields in user_objects view". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn what the created, last_ddl_time and timestamp fields mean in the user_objects view.

Meaning of created, last_ddl_time, timestamp fields in user_objects view

Created: the creation time of the object

Last_ddl_time: related to the object (not necessarily changing the structure of the object, but also other related, for example, if the object is a table, assigning select permission to the table to other users will also change the value of this field) the execution time of the last ddl operation

Timestamp: the time when the structure of the object changes, such as deleting fields, adding fields, etc.

SQL > conn dasong/dasong

Connected.

SQL > create table t_obj_time

2 (

3 col1 varchar2 (20)

4 col2 varchar2 (20)

5)

Table created.

SQL > col object_name for A20

SQL > alter session set nls_date_format='YYYY-MM-DD HH24:MI:SS'

Session altered.

If the table has just been created and no operation has been done on the table, the values of created, last_ddl_time and timestamp are the same.

SQL > select object_name, created, last_ddl_time, timestamp from user_objects where object_name='T_OBJ_TIME'

OBJECT_NAME CREATED LAST_DDL_TIME TIMESTAMP

T_OBJ_TIME 2012-02-10 08:56:05 2012-02-10 08:56:05 2012-02-10-02-10 purl 08 purl 56 purl 05

SQL > alter table t_obj_time add (col3 varchar2 (30))

Table altered.

-- after adding a field to the table, the values of last_ddl_time and timestamp are updated, and the values of last_ddl_time and timestamp remain the same, but are no longer the same as created

SQL > select object_name, created, last_ddl_time, timestamp from user_objects where object_name='T_OBJ_TIME'

OBJECT_NAME CREATED LAST_DDL_TIME TIMESTAMP

T_OBJ_TIME 2012-02-10 08:56:05 2012-02-10 08:57:23 2012-02-10-02-10 purl 08PUR 57 JV 23

SQL > grant select on t_obj_time to sys

Grant succeeded.

After the select permission of the table is assigned to the sys user, the LAST_DDL_TIME field is updated again, and the values of the three fields are different.

SQL > select object_name, created, last_ddl_time, timestamp from user_objects where object_name='T_OBJ_TIME'

OBJECT_NAME CREATED LAST_DDL_TIME TIMESTAMP

T_OBJ_TIME 2012-02-10 08:56:05 2012-02-10 08:57:49 2012-02-10-02-10 purl 08PUR 57 JV 23

At this point, I believe you have a deeper understanding of "what created, last_ddl_time, and timestamp fields mean in user_objects view". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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