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From Ali Akhtar <ali.rac...@gmail.com>
Subject Re: Ordering by multiple columns?
Date Mon, 10 Oct 2016 22:48:24 GMT
Okay.. so, how would you achieve the above scenario in cassandra?

On Tue, Oct 11, 2016 at 3:25 AM, Peddi, Praveen <peddi@amazon.com> wrote:

> That's not just a bad idea but that's impossible. Any field that is part
> of primary key is immutable. You should read up the Cassandra documentation
> and understand the basics before start using it. Otherwise you could easily
> abuse it inadvertently.
>
> Praveen
>
> On Oct 10, 2016, at 6:22 PM, Ali Akhtar <ali.rac200@gmail.com> wrote:
>
> E.g if I wanted to select * from foo where last_updated <= ?
>
> In this case, (I believe) last_updated will have to be a clustering key.
> If the record got updated and I wanted to update last_updated accordingly,
> that's a bad idea?
>
> :S
>
> On Tue, Oct 11, 2016 at 3:19 AM, Ali Akhtar <ali.rac200@gmail.com> wrote:
>
>> Huh - So if I wanted to search / filter by a timestamp field, and this
>> timestamp needed to get updated, that won't be possible?
>>
>> On Tue, Oct 11, 2016 at 3:07 AM, Nicolas Douillet <
>> nicolas.douillet@gmail.com> wrote:
>>
>>> If I correctly understand the answers, the solution to your ordering
>>> question is to use clustering keys.
>>> I'm agree, but I just wanted to warn you about one limitation :  the
>>> values of keys can't be updated, unless by using a delete and then an
>>> insert.
>>> (In the case of your song "example", putting the rate as a key can be
>>> tricky if the value has to be frequently updated)
>>>
>>>
>>> Le lun. 10 oct. 2016 à 22:15, Mikhail Krupitskiy <
>>> mikhail.krupitskiy@jetbrains.com> a écrit :
>>>
>>>> Looks like ordering by multiple columns in Cassandra has few sides that
>>>> are not obvious.
>>>> I wasn’t able to find this information in the official documentation
>>>> but it’s quite well described here:
>>>> http://stackoverflow.com/questions/35708118/where-and-order-
>>>> by-clauses-in-cassandra-cql
>>>>
>>>> Thanks,
>>>> Mikhail
>>>>
>>>> On 10 Oct 2016, at 21:55, DuyHai Doan <doanduyhai@gmail.com> wrote:
>>>>
>>>> No, we didn't record the talk this time unfortunately :(
>>>>
>>>> On Mon, Oct 10, 2016 at 8:17 PM, Ali Akhtar <ali.rac200@gmail.com>
>>>> wrote:
>>>>
>>>> Really helpful slides. Is there a video to go with them?
>>>>
>>>> On Sun, Oct 9, 2016 at 11:48 AM, DuyHai Doan <doanduyhai@gmail.com>
>>>> wrote:
>>>>
>>>> Yes it is possible, read this: http://www.slideshare.ne
>>>> t/doanduyhai/datastax-day-2016-cassandra-data-modeling-basics/24
>>>>
>>>> and the following slides
>>>>
>>>> On Sun, Oct 9, 2016 at 2:04 AM, Ali Akhtar <ali.rac200@gmail.com>
>>>> wrote:
>>>>
>>>> Is it possible to have multiple clustering keys in cassandra, or some
>>>> other way to order by multiple columns?
>>>>
>>>> For example, say I have a table of songs, and each song has a rating
>>>> and a date.
>>>>
>>>> I want to sort songs by rating first, and then with newer songs on top.
>>>>
>>>> So if two songs have 5 rating, and one's date is 1st Feb, the other is
>>>> 2nd Feb, then I want the 2nd feb one to be sorted above the 1st feb one.
>>>>
>>>> Like this:
>>>>
>>>> Select * from songs order by rating, createdAt
>>>>
>>>> Is this possible?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>
>

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