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From: "Jack" <sqljack@hotmail.com>
Newsgroups: comp.databases.oracle
Subject: object_id vs data_object_id in user_objects
Date: 2 Mar 2005 15:50:45 -0800
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I would like to ask for clarification on the meaning of these two
columns. According to the 9i Ref, object_id is the dictionary object
number of the object and data_object_id is the dictionary object number
of the segment that contains the object.

First question, what's the difference? Sorry to sound philosophic here,
but how could an object exist without a segment? Obviously it does, but
I could sure use some description of how to interpret the difference.

Second question,

Scenario:

Insert and commit two rows in a table.

Query user_objects for the table, object_id and data_object_id have the
identical value: 31264.

Delete both rows and commit, the columns still have identical values.

Reinsert the rows, commit and truncate the table, object_id is still
31264, data_object_id is now 31265.

Maybe the answer to my first question will clear this up, but at this
point I'm baffled about how the "style" of removing rows from a table
can cause the table's segment id to change? Isn't it the same segment?

Thanks for any illumination anyone can throw.

Jack