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From dawood abdullah <muhammed.daw...@gmail.com>
Subject Re: Versioning in cassandra
Date Mon, 02 Sep 2013 19:13:08 GMT
In my case version can be timestamp as well. What do you suggest version
number to be, do you see any problems if I keep version as counter /
timestamp ?


On Tue, Sep 3, 2013 at 12:22 AM, Jan Algermissen <jan.algermissen@nordsc.com
> wrote:

>
> On 02.09.2013, at 20:44, dawood abdullah <muhammed.dawood@gmail.com>
> wrote:
>
> > Requirement is like I have a column family say File
> >
> > create table file(id text primary key, fname text, version int, mimetype
> text, content text);
> >
> > Say, I have few records inserted, when I modify an existing record
> (content is modified) a new version needs to be created. As I need to have
> provision to revert to back any old version whenever required.
> >
>
> So, can version be a timestamp? Or does it need to be an integer?
>
> In the former case, make use of C*'s ordering like so:
>
> CREATE TABLE file (
>    file_id text,
>    version timestamp,
>    fname text,
>    ....
>    PRIMARY KEY (file_id,version)
> ) WITH CLUSTERING ORDER BY (version DESC);
>
> Get the latest file version with
>
> select * from file where file_id = 'xxx' limit 1;
>
> If it has to be an integer, use counter columns.
>
> Jan
>
>
> > Regards,
> > Dawood
> >
> >
> > On Mon, Sep 2, 2013 at 10:47 PM, Jan Algermissen <
> jan.algermissen@nordsc.com> wrote:
> > Hi Dawood,
> >
> > On 02.09.2013, at 16:36, dawood abdullah <muhammed.dawood@gmail.com>
> wrote:
> >
> > > Hi
> > > I have a requirement of versioning to be done in Cassandra.
> > >
> > > Following is my column family definition
> > >
> > > create table file_details(id text primary key, fname text, version
> int, mimetype text);
> > >
> > > I have a secondary index created on fname column.
> > >
> > > Whenever I do an insert for the same 'fname', the version should be
> incremented. And when I retrieve a row with fname it should return me the
> latest version row.
> > >
> > > Is there a better way to do in Cassandra? Please suggest what approach
> needs to be taken.
> >
> > Can you explain more about your use case?
> >
> > If the version need not be a small number, but could be a timestamp, you
> could make use of C*'s ordering feature , have the database set the new
> version as a timestamp and retrieve the latest one with a simple LIMIT 1
> query. (I'll explain more when this is an option for you).
> >
> > Jan
> >
> > P.S. Me being a REST/HTTP head, an alarm rings when I see 'version' next
> to 'mimetype' :-) What exactly are you versioning here? Maybe we can even
> change the situation from a functional POV?
> >
> >
> > >
> > > Regards,
> > >
> > > Dawood
> > >
> > >
> > >
> > >
> >
> >
>
>

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