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Subject: Re: mapping on non existing fields
From: Adam Kocoloski <kocolosk@apache.org>
In-Reply-To: <b05fcda40911040826xb77dd13xdee22201f4e1b84a@mail.gmail.com>
Date: Wed, 4 Nov 2009 13:59:43 -0500
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To: user@couchdb.apache.org

On Nov 4, 2009, at 11:26 AM, Duy Nguyen wrote:

> Hi,
>
> Im new to couchDB and im curious what couchDB behaves when I try to  
> MAPPING
> non-existing fields.
>
> For example:
>
> Document 1 has field1, field2, field3
> Document 2 has field1, fied4, field5
>
> function1 (doc) {
>      emit (doc.field1, doc.field4);
> }
>
> function2 (doc) {
>      emit (doc.field6, doc.field7);
> }
>
> What are the results from function 1 and function 2 ?
>
> Thanks.

function2 will throw an exception in the view server.  It's not fatal,  
but it's expensive, so not a good idea.  You should check for the  
presence of the field first.  Best,

Adam