Re: column ordering, was Re: [PATCHES] Enums patch v2

Tom Lane wrote:
> Martijn van Oosterhout <kleptog@svana.org> writes:
>   
>> On Thu, Dec 21, 2006 at 10:50:59AM -0500, Tom Lane wrote:
>>     
>>> Really?  To me that's one of a large number of questions that are
>>> unresolved about how we'd do this.  You can make a case for either
>>> choice in quite a number of places.
>>>       
>
>   
>> Can we? For anything of any permenence (view definitions, rules,
>> compiled functions, plans, etc) you're going to want the physical
>> number, for the same reason we store the oids of functions and tables.
>>     
>
> Not if we intend to rearrange the physical numbers during column
> add/drop to provide better packing.
>
> You could make a case that we need *three* numbers: a permanent column
> ID, a display position, and a storage position.
>
>
>   

Could this not be handled by some catalog fixup after an add/drop? If we 
get the having 3 numbers you will almost have me convinced that this 
might be too complicated after all.

cheers

andrew