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From: Praveen Baratam <praveen.baratam@gmail.com>
Date: Thu, 23 Feb 2012 12:38:24 +0530
Message-ID: 
 <CAAQs3wtRinCNSX0NP8sKxSaNkvdp-GYtjcOQWK9gWU5UAyW2DQ@mail.gmail.com>
Subject: Re: How to delete a range of columns using first N components of
 CompositeType Column?
To: user@cassandra.apache.org
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More precisely,

Lets say we have a CF with the following spec.

create column family Test
    with comparator = 'CompositeType(UTF8Type,UTF8Type,UTF8Type)'
    and key_validation_class = 'UTF8Type'
    and default_validation_class = 'UTF8Type';

And I have columns such as:

Jack:Name:First - Jackson
Jack:Name:Last -  Samuel
Jack:Age - 50

Now To delete all columns related to Jack, I need to use as far as I can
comprehend

Delete 'Jack:Name:First', 'Jack:Name:Last', 'Jack:Age' from Test where KEY
= "friends";

The problem is we do not usually know what meta-data is associated with a
user as it may include Timestamp based columns.

such as: Jack:1234567890:Location - Chicago

Can something like -

Delete 'Jack' from Test where KEY = "friends";

be done using the First N components of the CompositeType?

Or should we read first and then delete?

Thank You.

On Thu, Feb 23, 2012 at 4:47 AM, Praveen Baratam
<praveen.baratam@gmail.com>wrote:

> I am using CompositeType columns and its very convenient to query for a
> range of columns using the *First N *components but how do I delete a
> range of columns using the First N components of the CompositeType column.
>
> In order to specify the exact column names to delete, I would have to read
> first and then delete.
>
> Is there a better way?
>

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More precisely,<div><br></div><div>Lets say we have a CF with the following=
 spec.</div><div><br></div><div><div>create column family Test</div><div>=
=A0 =A0 with comparator =3D &#39;CompositeType(UTF8Type,UTF8Type,UTF8Type)&=
#39;</div>

<div>=A0 =A0 and key_validation_class =3D &#39;UTF8Type&#39;</div><div>=A0 =
=A0 and default_validation_class =3D &#39;UTF8Type&#39;; =A0 =A0</div><div>=
<br></div><div>And I have columns such as:</div><div><br></div><div>Jack:Na=
me:First - Jackson</div>

<div>Jack:Name:Last - =A0Samuel</div><div>Jack:Age - 50</div><div><br></div=
><div>Now To delete all columns related to Jack, I need to use as far as I =
can comprehend</div><div><br></div><div>Delete &#39;Jack:Name:First&#39;, &=
#39;Jack:Name:Last&#39;, &#39;Jack:Age&#39; from Test where KEY =3D &quot;f=
riends&quot;;</div>

<div><br></div><div>The problem is we do not usually know what meta-data is=
 associated with a user as it may include Timestamp based columns.</div><di=
v><br></div><div>such as: Jack:1234567890:Location - Chicago</div><div>

<br></div><div>Can something like -</div><div><br></div><div>Delete &#39;Ja=
ck&#39; from Test where KEY =3D &quot;friends&quot;;</div><div><br></div><d=
iv>be done using the First N components of the CompositeType?</div><div>
<br>
</div><div>Or should we read first and then delete?</div><div><br></div><di=
v>Thank You.</div><br><div class=3D"gmail_quote">On Thu, Feb 23, 2012 at 4:=
47 AM, Praveen Baratam <span dir=3D"ltr">&lt;<a href=3D"mailto:praveen.bara=
tam@gmail.com">praveen.baratam@gmail.com</a>&gt;</span> wrote:<br>

<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">I am using CompositeType columns and its ver=
y convenient to query for a range of columns using the <b>First N </b>compo=
nents but how do I delete a range of columns using the First N components o=
f the CompositeType column.<div>


<br></div><div>In order to specify the exact column names to delete, I woul=
d have to read first and then delete.</div><div><br></div><div>Is there a b=
etter way?</div>
</blockquote></div><br></div>

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