Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!mtxinu!sybase!jeffl@sybase.Sybase.COM
From: jeffl@sybase.Sybase.COM (Jeff Lichtman)
Newsgroups: comp.databases
Subject: Re: Parsing Query Languages in the Client or Server
Message-ID: <6167@sybase.sybase.com>
Date: 21 Sep 89 05:36:55 GMT
References: <6155@sybase.sybase.com>
Sender: news@sybase.sybase.com
Lines: 26

> At Britton Lee
> query languages were parsed in the clients and parse trees were sent
> to the server. Here at Sybase we send the query language to the
> server to be parsed.

I believe the latter approach is better.  The world is moving toward
open, standardized interfaces.  There is already an ANSI SQL standard,
and a subcommittee of ANSI X3H2 is working on remote database access
protocols.  Eventually, a client will be able to run queries on anyone's
server without having to know much about the server.  If sending parse
trees across the network becomes the standard, then the format of the
parse trees and the protocol for sending them will have to be part of
the standard.  RDA stuff is hard enough without introducing this problem.

> Detecting syntax errors in the client can prevent sending a
> syntactically incorrect query over a potentially slow network.
> It would take fewer resources to find out that a query is syntactically
> incorrect.

This is only important when users are doing ad hoc queries.  When most
of the queries are embedded in the application, or are pre-compiled,
there is next to no possibility of getting a syntax error.
---
Jeff Lichtman at Sybase
{mtxinu,pacbell}!sybase!jeffl  -or- jeffl@sybase.com
"Saints should always be judged guilty until they are proved innocent..."