Hi,

Sorry, this is a PIG newbie question...

When I use FLATTEN, I don't understand the structure of the relation that
is returned.

For example, the following relation A is the result of using flatten:

DESCRIBE A;

A {null::group: chararray,null::tagcount: long}

I'm not really sure why there is "null" prefixing group and tagcount. Can
anyone help explain what this means?

Thanks,
James

this is a very good explanation of flatten:

http://ofps.oreilly.com/titles/9781449302641/advanced_pig_latin.html#foreach_flatten

On Wed, Apr 11, 2012 at 9:46 AM, James Newhaven <[EMAIL PROTECTED]>wrote:

> Hi,
>
> Sorry, this is a PIG newbie question...
>
> When I use FLATTEN, I don't understand the structure of the relation that
> is returned.
>
> For example, the following relation A is the result of using flatten:
>
> DESCRIBE A;
>
> A {null::group: chararray,null::tagcount: long}
>
> I'm not really sure why there is "null" prefixing group and tagcount. Can
> anyone help explain what this means?
>
> Thanks,
> James
>

Thanks Pablo,

That link was really useful. The reason the fieldnames contain NULL, is
that I used FLATTEN with TOP, which currently discards the bagname. This is
going to be fixed in 0.11 as per
https://issues.apache.org/jira/browse/PIG-2365

On Wed, Apr 11, 2012 at 2:55 PM, pablomar
<[EMAIL PROTECTED]>wrote:

> this is a very good explanation of flatten:
>
>
> http://ofps.oreilly.com/titles/9781449302641/advanced_pig_latin.html#foreach_flatten
>
>
>
> On Wed, Apr 11, 2012 at 9:46 AM, James Newhaven <[EMAIL PROTECTED]
> >wrote:
>
> > Hi,
> >
> > Sorry, this is a PIG newbie question...
> >
> > When I use FLATTEN, I don't understand the structure of the relation that
> > is returned.
> >
> > For example, the following relation A is the result of using flatten:
> >
> > DESCRIBE A;
> >
> > A {null::group: chararray,null::tagcount: long}
> >
> > I'm not really sure why there is "null" prefixing group and tagcount. Can
> > anyone help explain what this means?
> >
> > Thanks,
> > James
> >
>