RE : full featured alter table?

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От Ernest E Vogelsinger
Тема RE : full featured alter table?
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Msg-id 5.1.1.6.2.20030616000519.02deaa78@mail.vogelsinger.at
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Ответ на Re: full featured alter table?  (Ernest E Vogelsinger <ernest@vogelsinger.at>)
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At 23:30 15.06.2003, Bruno BAGUETTE said:
--------------------[snip]--------------------
>> If some frontende decides to display the columns in a
>> particular order, ok, but it should store this order
>> somewhere else, either in its own private tables, a
>> configuration or ini file, or elsewhere. It simply doesn't
>> belong to the database layout, or pg_attribute.
>
>I disagree, I don't like when frontends and other GUI are creating new
>tables in the database. Plus, if I use a frontend (pgAdmin, for example)
>to set the columns order, I want to get that presentation order when I
>do a SELECT * using the PostgreSQL API or using the psql frontend...
>
>So, storing the columns order in the pg_attributes table is, I think, a
>good solution. :-)
--------------------[snip]--------------------

This may come in handy of you're the only one using the database.

What if:
a) multiple users/developers are "maintaining" their own "private" column
ordering?
b) what happens to those (poorly written but existing) applications that
use columnless INSERTs? Will they break or what?

I don't think changing the column order in pg_attributes would be a good
thing - too much to break loose. Maybe there could be something non-SQL
conforming
   CREATE COLUMNORDER "order_name" ON TABLE "table_name" ("column", ...)
and you could use this with a SELECT extension:
   SELECT * FROM "table_name" COLUMNORDER "order_name"

but that can be easily done using views:
   CREATE VIEW "viewname" AS SELECT (col3, col5, col2) FROM "table_name"

Well, views are read-only unless you're using an appropriate rule.


--
   >O     Ernest E. Vogelsinger
   (\)    ICQ #13394035
    ^     http://www.vogelsinger.at/



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