Re: Altering a table - positioning new columns

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От Chris Boget
Тема Re: Altering a table - positioning new columns
Дата
Msg-id 02b101c2c09f$26d21370$8c01a8c0@ENTROPY
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Ответ на Altering a table - positioning new columns  ("Chris Boget" <chris@wild.net>)
Ответы Re: Altering a table - positioning new columns  (Manfred Koizar <mkoi-pg@aon.at>)
Список pgsql-general
> >I'm curious how difficult this would be to implement...
> The current implementation has the benefit that when you add a column
> existing tuples don't have to be touched.

Hmm, I was under the (obvious) (mis)understanding that a tuple was a
record.  Is that not the case?  If not, what is it, then?

> Each tuple header stores the number of attributes (natts) at the time of
> its creation.  If you query for an attribute with a higher number, you get
> NULL.  I don't think this can be changed easily without breaking lots of
> things.

How do the new columns fit into the above scheme?

Chris


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