Hello,
There are probably lots of options to this challenge. The more details
around your use case that you can provide, the easier it will be for this
group to offer advice.
A few follow-up questions:
- How will you query this data?
- Do your queries require filtering on specific columns other than
product_id and created_at, i.e. the dynamic columns?
Depending on the answers to these questions, you have several options, of
which here are a few:
- Cassandra efficiently stores sparse data, so you could create columns
and not populate them, without much of a penalty
- Could use a clustering column to store a columns type and another col
(potentially clustering) to store the value
- i.e. CREATE TABLE foo (col1 int, attname text, attvalue text,
col4...n, PRIMARY KEY (col1, attname, attvalue));
- where attname stores the name of the attribute/column and attvalue
stores the value of that attribute
- have seen users use this model and create a "main" attribute row
within a partition that stores the values associated with col4...n
- Could store multiple collections
- Others probably have ideas as well
You may want to look in the archives for a similar discussion topic.
Believe this item was asked a few months ago as well.
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Jonathan Lacefield
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On Tue, Jan 20, 2015 at 1:40 PM, chetan verma <chetanverm...@gmail.com>
wrote:
> Hi,
>
> I am creating a review system. for instance lets assume following are the
> attibutes of system:
>
> Review{
> id bigint,
> product_id bigint,
> created_at timestamp,
> summary text,
> description text,
> pros set<text>,
> cons set<text>,
> feature_rating map<text, int>
> etc....
> }
> I created partition key as product_id (so that all the reviews for a given
> product will reside on same node)
> and clustering key as created_at and id (Desc) so that reviews will be
> sorted by time.
>
> I can have more column and that requirement I want to fulfil by dynamic
> columns but there are limitations to it explained above.
> Could you please let me know the best way.
>
> On Tue, Jan 20, 2015 at 11:59 PM, Jonathan Lacefield <
> jlacefi...@datastax.com> wrote:
>
>> Hello,
>>
>> Have you looked at solving this challenge with clustering columns?
>> Also, please describe the problem set details for more specific advice from
>> this group.
>>
>> Starting new projects on Thrift isn't the recommended approach.
>>
>> Jonathan
>>
>> [image: datastax_logo.png]
>>
>> Jonathan Lacefield
>>
>> Solution Architect | (404) 822 3487 | jlacefi...@datastax.com
>>
>> [image: linkedin.png] <http://www.linkedin.com/in/jlacefield/> [image:
>> facebook.png] <https://www.facebook.com/datastax> [image: twitter.png]
>> <https://twitter.com/datastax> [image: g+.png]
>> <https://plus.google.com/+Datastax/about>
>> <http://feeds.feedburner.com/datastax> <https://github.com/datastax/>
>>
>> On Tue, Jan 20, 2015 at 1:24 PM, chetan verma <chetanverm...@gmail.com>
>> wrote:
>>
>>> Hi,
>>>
>>> I am starting a new project with cassandra as database.
>>> I have unstructured data so I need dynamic columns,
>>> though in CQL3 we can achive this via Collections but there are some
>>> downsides to it.
>>> 1. Collections are used to store small amount of data.
>>> 2. The maximum size of an item in a collection is 64K.
>>> 3. Cassandra reads a collection in its entirety.
>>> 4. Restrictions on number of items in collections is 64,000
>>>
>>> And no support to get single column by map key, which is possible via
>>> cassandra cli.
>>> Please suggest whether I should use CQL3 or Thrift and which driver is
>>> best.
>>>
>>> --
>>> *Regards,*
>>> *Chetan Verma*
>>> *+91 99860 86634 <%2B91%2099860%2086634>*
>>>
>>
>>
>
>
> --
> *Regards,*
> *Chetan Verma*
> *+91 99860 86634 <%2B91%2099860%2086634>*
>
