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Re: null columns and memory?

From: Yechiel Adar <adar76_at_inter.net.il>
Date: Wed, 28 Sep 2005 16:26:23 +0200
Message-ID: <433AA80F.4080601@inter.net.il>


Oracle does not store CL for trailing null columns. Since you add a column at the end, if it is null the oracle just update the dictionary.
You can check it out easily by add null column to empty table and to table that have a lot of data.
The time will be the same.
If you add column with default value then oracle will update each row with the new value and then size will matter.

Adar Yechiel
Rechovot, Israel

Ram K wrote:

> A related question:
>
> Let us say there is block that contains 25 rows for a table with 2
> columns:
>
> RH|CL|CD|CL|CD|RH|CL|CD|CL|CD|RH|CL|CD|CL|CD|.....
>
> and we add a new column to the table, will the data be stored like this:
>
> Case 1:
> RH|CL|CD|CL|CD|NewColLnth|Newcol|RH|CL|CD|CL|CD|NewColLnth|Newcol|...
>
>

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Received on Wed Sep 28 2005 - 08:28:45 CDT

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