Re: Is ALTER TABLE ADD COLUMN a time-consuming operation ?

If the new column is nullable, it should very little time, since all that happens is an update to the dictionary. If it is not null, then the column will have to be physically added to each row with a value.

>>> EShevtsov_at_flagship.ru 04/05/01 07:15AM >>>
Hello List

We are going to change structure of a big table (more than 250.000.000 rows).
We need to add a column with NUMBER type. I'm unclear how Oracle do this operation.  Does it mean that Oracle have to read and reformat all table blocks in order to update each row header? If yes, I can suggest that estimation of the operation's time is about time of Full Table Scan on the table.
Is it correct? Please explain.

Ed

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