Not sure if you remember this Jonathan, but Sylvain already wrote a very clear documentation about it : http://www.datastax.com/dev/blog/thrift-to-cql3 (OCTOBER 26, 2012)

Yet a second page will give to this important topic a greater visibility.


2013/6/6 Jonathan Ellis <jbellis@gmail.com>
This is becoming something of a FAQ, so I wrote an more in-depth
answer: http://www.datastax.com/dev/blog/does-cql-support-dynamic-columns-wide-rows

On Thu, Jun 6, 2013 at 8:02 AM, Joe Greenawalt <joe.greenawalt@gmail.com> wrote:
> Hi,
> I'm having some problems figuring out how to append a dynamic column on a
> column family using the datastax java driver 1.0 and CQL3 on Cassandra
> 1.2.5.  Below is what i'm trying:
>
> cqlsh:simplex> create table user (firstname text primary key, lastname
> text);
> cqlsh:simplex> insert into user (firstname, lastname) values
> ('joe','shmoe');
> cqlsh:simplex> select * from user;
>
>  firstname | lastname
> -----------+----------
>        joe |    shmoe
>
> cqlsh:simplex> insert into user (firstname, lastname, middlename) values
> ('joe','shmoe','lester');
> Bad Request: Unknown identifier middlename
> cqlsh:simplex> insert into user (firstname, lastname, middlename) values
> ('john','shmoe','lester');
> Bad Request: Unknown identifier middlename
>
> I'm assuming you can do this based on previous based thrift based clients
> like pycassa, and also by reading this:
>
> The Cassandra data model is a dynamic schema, column-oriented data model.
> This means that, unlike a relational database, you do not need to model all
> of the columns required by your application up front, as each row is not
> required to have the same set of columns. Columns and their metadata can be
> added by your application as they are needed without incurring downtime to
> your application.
>
> here: http://www.datastax.com/docs/1.2/ddl/index
>
> Is it a limitation of CQL3 and its connection vs. thrift?
> Or more likely i'm just doing something wrong?
>
> Thanks,
> Joe



--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder, http://www.datastax.com
@spyced