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From Sasha Dolgy <sdo...@gmail.com>
Subject Re: How to store a list of values?
Date Mon, 26 Mar 2012 17:26:47 GMT
Save the skills in a single column in json format.  Job done.
On Mar 26, 2012 7:04 PM, "Ben McCann" <ben@benmccann.com> wrote:

> True.  But I don't need the skills to be searchable, so I'd rather embed
> them in the user than add another top-level CF.  I was thinking of doing
> something along the lines of adding a skills super column to the User table:
>
> skills: {
>   'java': null,
>   'c++': null,
>   'cobol': null
> }
>
> However, I'm still not sure yet how to accomplish this with Astyanax.
>  I've only figured out how to make composite columns with predefined column
> names with it and not dynamic column names like this.
>
>
>
> On Mon, Mar 26, 2012 at 9:08 AM, R. Verlangen <robin@us2.nl> wrote:
>
>> In this case you only neem the columns for values. You don't need the
>> column-values to hold multiple columns (the super-column principle). So a
>> normal CF would work.
>>
>>
>> 2012/3/26 Ben McCann <ben@benmccann.com>
>>
>>> Thanks for the reply Samal.  I did not realize that you could store a
>>> column with null value.  Do you know if this solution would work with
>>> composite columns?  It seems super columns are being phased out in favor of
>>> composites, but I do not understand composites very well yet.  I'm trying
>>> to figure out if there's any way to accomplish what you've suggested using
>>> Astyanax <https://github.com/Netflix/astyanax>.
>>>
>>> Thanks for the help,
>>> Ben
>>>
>>>
>>> On Mon, Mar 26, 2012 at 8:46 AM, samal <samalgorai@gmail.com> wrote:
>>>
>>>> plus it is fully compatible with CQL.
>>>> SELECT * FROM UserSkill WHERE KEY='ben';
>>>>
>>>>
>>>> On Mon, Mar 26, 2012 at 9:13 PM, samal <samalgorai@gmail.com> wrote:
>>>>
>>>>> 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
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>>
>> --
>> With kind regards,
>>
>> Robin Verlangen
>> www.robinverlangen.nl
>>
>>
>

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