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

Martijn van Oosterhout wrote:
> On Wed, Dec 20, 2006 at 07:20:14AM -0600, Kenneth Marshall wrote:
>   
>> On Wed, Dec 20, 2006 at 01:26:59PM +0100, Peter Eisentraut wrote:
>>     
>>> Am Mittwoch, 20. Dezember 2006 04:44 schrieb Tom Lane:
>>>       
>>>> If you can show me a reasonably bulletproof or machine-checkable way to
>>>> keep the two kinds of column numbers distinct, I'd be all for it.
>>>>         
>>> The only way I can see is to make the domains of the numbers distinct.
>>>
>>>       
>> Negative vs. positive numbers?
>>     
>
> Negative is used by system columns. Just adding some large constant
> (say 10000) should be enough.
>
> Have a nice day,
>   

Or we could divide the positive number space in two, by starting at 2^14 
(attnums are int2). Then a simple bitmask test would work to distinguish 
them.


cheers

andrew