Re: ENUM type - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: ENUM type
Date
Msg-id 42E7A882.5020900@dunslane.net
Whole thread Raw
In response to Re: ENUM type  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers

Tom Lane wrote:

>"Jim C. Nasby" <decibel@decibel.org> writes:
>  
>
>>... what I was wondering about is creating a
>>'type' that is a rollup for:
>>    
>>
>
>  
>
>>- create parent table with int id field and text and indexes
>>- add RI to base table
>>- add triggers/views/rules/other glue to make the id field hidden and
>>  transparent to users in normal uses
>>    
>>
>
>Given the difficulties we've had with SERIAL columns, this seems much
>less than trivial :-(.  I'd be interested to see a good solution ---
>I suspect it needs one or two ideas we haven't had yet.
>
>In the meantime, I agree with Andrew's reply that the best stopgap is to
>invent a bespoke datatype for each required ENUM set, with input and
>output functions that have the list of values hardwired in.
>
>
>  
>

:-)

Can you expand a bit on how it might work? It's not totally clear to me 
:-)  Can we use an incomplete type as a parameter for anything except a 
C function? Maybe we could do it with a single C function that would 
retrieve the values from the catalog (extra col in pg_type?) and build 
(and cache) the translation tables.


This could be an excellent intern project, BTW.

cheers

andrew




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