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Date: Mon, 26 Mar 2012 21:13:13 +0530
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 <CAP=kKf_onUSyv_gsT91m11VxAibv7=i66Zfg5V5cE2E2do_F_w@mail.gmail.com>
Subject: Re: How to store a list of values?
From: samal <samalgorai@gmail.com>
To: user@cassandra.apache.org
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I would take simple approach. create one other CF "UserSkill"  with row key
same as profile_cf key,
In user_skill cf will add skill as column name and value null. Columns can
be added or removed.

UserProfile={
  '*ben*'={
   blah :blah
   blah :blah
   blah :blah
 }
}

UserSkill={
  '*ben*'={
    'java':''
    'cassandra':''
  .
  .
  .
  'linux':''
  'skill':'infinity'
 }

}


On Mon, Mar 26, 2012 at 12:34 PM, Ben McCann <ben@benmccann.com> wrote:

> I have a profile column family and want to store a list of skills in each
> profile.  In BigTable I could store a Protocol Buffer<http://code.google.com/apis/protocolbuffers/docs/overview.html>with a repeated field, but I'm not sure how this is typically accomplished
> in Cassandra.  One option would be to store a serialized Thrift<http://thrift.apache.org/>or protobuf, but I'd prefer not to do this as I believe Cassandra doesn't
> have knowledge of these formats, and so the data in the datastore would not
> not human readable in CQL queries from the command line.  The other
> solution I thought of would be to use a super column and put a random UUID
> as the key for each skill:
>
> skills: {
>   '4b27c2b3ac48e8df': 'java',
>   '84bf94ea7bc92018': 'c++',
>   '9103b9a93ce9d18': 'cobol'
> }
>
> Is this a good way of handling lists in Cassandra?  I imagine there's some
> idiom I'm not aware of.  I'm using the Astyanax<https://github.com/Netflix/astyanax/wiki>client library, which only supports composite columns instead of super
> columns, and so the solution I proposed above would seem quite awkward in
> that case.  Though I'm still having some trouble understanding composite
> columns as they seem not to be completely documented yet.  Would this
> solution work with composite columns?
>
> Thanks,
> Ben
>
>

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I would take simple approach. create one other CF &quot;UserSkill&quot;=C2=
=A0 with row key same as profile_cf key, <br>In user_skill cf will add skil=
l as column name and value null. Columns can be added or removed.<br><br>Us=
erProfile=3D{<br>
=C2=A0 &#39;<b>ben</b>&#39;=3D{<br>=C2=A0=C2=A0 blah :blah<br>=C2=A0=C2=A0 =
blah :blah<br>=C2=A0=C2=A0 blah :blah<br>=C2=A0}<br>}<br><br>UserSkill=3D{<=
br>=C2=A0 &#39;<b>ben</b>&#39;=3D{<br>=C2=A0=C2=A0=C2=A0 &#39;java&#39;:=
9;&#39;<br>=C2=A0=C2=A0=C2=A0 &#39;cassandra&#39;:&#39;&#39;<br>=C2=A0 .<br=
>=C2=A0 .<br>
=C2=A0 .<br>=C2=A0 &#39;linux&#39;:&#39;&#39;<br>=C2=A0 &#39;skill&#39;:=
9;infinity&#39;<br>=C2=A0}<br><br>}<br><br><br><div class=3D"gmail_quote">O=
n Mon, Mar 26, 2012 at 12:34 PM, Ben McCann <span dir=3D"ltr">&lt;<a href=
=3D"mailto:ben@benmccann.com">ben@benmccann.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 have a profile column family and want to s=
tore a list of skills in each profile. =C2=A0In BigTable I could store a <a=
 href=3D"http://code.google.com/apis/protocolbuffers/docs/overview.html" ta=
rget=3D"_blank">Protocol Buffer</a> with a repeated field, but I&#39;m not =
sure how this is typically accomplished in Cassandra. =C2=A0One option woul=
d be to store a serialized <a href=3D"http://thrift.apache.org/" target=3D"=
_blank">Thrift</a> or protobuf, but I&#39;d prefer not to do this as I beli=
eve Cassandra doesn&#39;t have knowledge of these formats, and so the data =
in the datastore would not not human readable in CQL queries from the comma=
nd line. =C2=A0The other solution I thought of would be to use a super colu=
mn and put a random UUID as the key for each skill:<div>

<br></div><div>skills: {</div><div>=C2=A0 &#39;4b27c2b3ac48e8df&#39;: &#39;=
java&#39;,</div><div>=C2=A0 &#39;84bf94ea7bc92018&#39;: &#39;c++&#39;,</div=
><div>=C2=A0 &#39;9103b9a93ce9d18&#39;: &#39;cobol&#39;</div><div>}</div><d=
iv><br></div>

<div>Is this a good way of handling lists in Cassandra? =C2=A0I imagine the=
re&#39;s some idiom I&#39;m not aware of. =C2=A0I&#39;m using the <a href=
=3D"https://github.com/Netflix/astyanax/wiki" target=3D"_blank">Astyanax</a=
> client library, which only supports composite columns instead of super co=
lumns, and so the solution I proposed above would seem quite awkward in tha=
t case. =C2=A0Though I&#39;m still having some trouble understanding compos=
ite columns as they seem not to be completely documented yet. =C2=A0Would t=
his solution work with composite columns?</div>

<div><br></div><div>Thanks,</div><div>Ben</div><div><br></div>
</blockquote></div><br>

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