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From Jack Krupansky <jack.krupan...@gmail.com>
Subject Re: UUID question
Date Mon, 23 Nov 2015 16:50:24 GMT
The point is to have a unique, generated ID for each entity, to ensure
absolute uniqueness. In the old days each app had its own technique for
generating unique IDs. Now we have UUIDs, which are unique, but are
generated uniformly across systems and applications. Uniqueness is
guaranteed even if an account is closed and reopened. Email addresses and
user IDs (user-assigned) can of course be reused.

You could also have an application-generated account number and use that as
the unique key, with user ID, user name, and email as alternate keys.

-- Jack Krupansky

On Mon, Nov 23, 2015 at 11:31 AM, Prem Yadav <ipremyadav@gmail.com> wrote:

> OK.
> My question is more about what are the use case of any table uuid as
> partition key.
> Will appreciate inputs from others.
>
> Thanks,
> Prem
>
> On Mon, Nov 23, 2015 at 4:25 PM, Jay Reddy <jayreddy123@gmail.com> wrote:
>
>> Hi Prem,
>>
>> We have two tables, one with email id as partition key and other with
>> userid(uuid).
>> Please refer to www.killrvideo.com website. It is a great place to
>> understand how a web application is built on Cassandra.
>>
>> Thanks,
>> Jay
>>
>> On Mon, Nov 23, 2015 at 11:18 AM, Prem Yadav <ipremyadav@gmail.com>
>> wrote:
>>
>>> Thanks Jay. Now this is great while creating the user. How does the user
>>> change the details? let's say email id or password? How do you lookup the
>>> user table?
>>>
>>>
>>> On Mon, Nov 23, 2015 at 4:14 PM, Jay Reddy <jayreddy123@gmail.com>
>>> wrote:
>>>
>>>> Here is one use case ..
>>>>
>>>> We are designing  a web application using Cassandra.
>>>> When a user signs on we create user info in user table with userid
>>>> (uuid) is primary and is responded back to UI.
>>>>
>>>> UI uses this UUID for any future communications.  UI can also get user
>>>> id when searched for an user detail  in "search" (achieved by Solr).
>>>>
>>>> Thanks,
>>>> Jay
>>>>
>>>> On Mon, Nov 23, 2015 at 11:08 AM, Prem Yadav <ipremyadav@gmail.com>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I am trying to understand different use cases related to using UUID as
>>>>> the partition key. I am sure I am missing something trivial and will
be
>>>>> grateful and you can help me understand this.
>>>>>
>>>>> When do you use the UUID as the primary key? What can be a use case?
>>>>> Since it is unique, how do you query it?
>>>>>
>>>>> Let's take a user table with UUID as primary key.
>>>>>
>>>>> create table user (id uuid primary key, name varchar,company
>>>>> varchar,country varchar);
>>>>>
>>>>> Now I can write to the table using the uuid() function to generate the
>>>>> uid. But how do you query it?
>>>>> The only use case I see is create a secondary index and use that for
>>>>> querying.
>>>>>
>>>>> Am I missing something here?
>>>>>
>>>>> Thanks,
>>>>> Prem
>>>>>
>>>>
>>>>
>>>
>>
>

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