Re: what is user_objects.DATA_OBJECT_ID?

The data_object_id is an identifier for the physical data segment currently holding data for the object_id. This allows Oracle to track objects logically, even if you do things like 'rebuild index', 'truncate table'.

In answer to the NULL data_object_id - this may be because COREREF_ABSTRACT is partitioned in one database, so the object never has its own data segment, but its partitions do; whilst it is not partitioned in the other database - on the other hand we can see from the other database that the object_id does not match the data_object_id, so it must have been truncated or rebuilt at least once. (Note also the discrepancy between CREATED date and LAST_DDL date)

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G M wrote in message <50a5e6b6.0203071314.7ba72709_at_posting.google.com>...


>Hi:

>

>I have a question about user_objects.DATA_OBJECT_ID column.

>

>According to Oracle's Documentation:

>

>-------

>DATA_OBJECT_ID   NUMBER

>

>Dictionary object number of the segment that contains the object

>

>Note: OBJECT_ID and DATA_OBJECT_ID display data dictionary metadata.

>Do not confuse these numbers with the unique 16-byte object identifier

>("object ID") that Oracle assigns to row objects in object tables in

>the system.

>--------

>

>We have two databases and in them there is one index that I am trying

>to compare. The only difference is that one of them has

>"DATA_OBJECT_ID" null. What does that mean?

>

>on db1:

>

>SQL> select * from user_objects where object_name =

>'COREREF_ABSTRACT';

>

>OBJECT_NAME

>---------------------------------------------------------------------------

-----


>SUBOBJECT_NAME                  OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE

>------------------------------ ---------- --------------

>------------------

>CREATED   LAST_DDL_ TIMESTAMP           STATUS  T G S

>--------- --------- ------------------- ------- - - -

>COREREF_ABSTRACT

>                                     6281                INDEX

>08-FEB-02 08-FEB-02 2002-02-08:05:11:46 VALID   N N N

>

>

>

>on db2:

>

>SQL> select * from user_objects where object_name =

>'COREREF_ABSTRACT';

>

>OBJECT_NAME

>---------------------------------------------------------------------------

-----


>SUBOBJECT_NAME                  OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE

>------------------------------ ---------- --------------

>------------------

>CREATED   LAST_DDL_ TIMESTAMP           STATUS  T G S

>--------- --------- ------------------- ------- - - -

>COREREF_ABSTRACT

>                                     4928           9401 INDEX

>11-SEP-00 03-MAR-02 2000-09-11:16:55:12 VALID   N N N