FETCH statement again

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От Michael Meskes
Тема FETCH statement again
Дата
Msg-id 20000113153916.B1071@fam-meskes.de
обсуждение исходный текст
Список pgsql-hackers
I just got a reply from the original author of the patch I was talking
about:

----- Forwarded message from Rene Hogendoorn <hogend@nlr.nl> -----

From: Rene Hogendoorn <hogend@nlr.nl>
Date: Thu, 13 Jan 2000 14:23:08 +0100 (MET)
To: Michael Meskes <michael@fam-meskes.de>
Subject: Re: ECPG patches
   TL> Michael Meskes <meskes@postgreSQL.org> writes:   >> <fetch statement> ::= FETCH [ [ <fetch orientation> ] FROM ]
 >> <cursor name> INTO <fetch target list>
 
   >> To me this seems to say that FROM is just optional. Okay, if I   >> make it optional in our parser?
   TL> Careful --- notice that FROM is only optional if you *also*   TL> omit all the preceding optional clauses.
Otherwisethere will   TL> be a reduce conflict that you could only resolve by removing   TL> all of FETCH's secondary
keywordsfrom the ColId list.  I   TL> don't think that would be an acceptable tradeoff.
 

The reduce conflict is caused by the /* EMPTY */ alternatives of
'opt_direction', 'fetch_how_many' and 'opt_portal_name'.  Considering
the sql92 syntax, 'opt_portalname' is wrong; the portalname is not
optional, but required. Requiring a portalname also solves the problem
of 'EXEC SQL FETCH; being a valid statement.
Furthermore, at least INFORMIX supports 'FETCH NEXT t1;'. So, I strongly
suggest to NOT require 'FROM'.
...
Regards
Rene
-- 

R. A. Hogendoorn                                       E-mail: hogend@nlr.nl
Information and Communication Technology Division      Tel. +31-527-24-8367 
National Aerospace Laboratory, The Netherlands         Fax. +31-527-24-8210 

----- End forwarded message -----

Michael
-- 
Michael Meskes                         | Go SF 49ers!
Th.-Heuss-Str. 61, D-41812 Erkelenz    | Go Rhein Fire!
Tel.: (+49) 2431/72651                 | Use Debian GNU/Linux!
Email: Michael@Fam-Meskes.De           | Use PostgreSQL!


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