incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jeremiah Jordan <jerem...@datastax.com>
Subject Re: CREATE COLUMNFAMILY
Date Mon, 12 Nov 2012 00:11:32 GMT
That is fine.  You just have to be careful that you haven't already inserted data which would
be rejected by the type you update to, as a client will have issues reading that data back.

-Jeremiah

On Nov 11, 2012, at 4:09 PM, Kevin Burton <rkevinburton@charter.net> wrote:

> What happens when you are mainly concerned about the human readable formats? Say initially
you don’t supply metadata for a key like foo in the column family, but you get tired of
seeing binary data displayed for the values so you update the column family to get a more
human readable format by adding metadata for foo. Will this work?
>  
> From: aaron morton [mailto:aaron@thelastpickle.com] 
> Sent: Sunday, November 11, 2012 3:39 PM
> To: user@cassandra.apache.org
> Subject: Re: CREATE COLUMNFAMILY
>  
> Also most idomatic clients use the information so they can return the appropriate type
to you. 
>  
>  Can the metadata be applied
> after the fact? If so how?
> UPDATE COLUMN FAMILY in the CLI will let you change it. 
> Note that we do not update the existing data. This can be a problem if you do something
like change a variable length integer to a fixed length one. 
>  
> Cheers
>  
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>  
> On 12/11/2012, at 8:06 AM, Kevin Burton <rkevinburton@charter.net> wrote:
> 
> 
> Thank you this helps with my understanding. 
> 
> So the goal here is to supply as many name/type pairs as can be reasonably
> be foreseen when the column family is created? Can the metadata be applied
> after the fact? If so how?
> 
> -----Original Message-----
> From: Edward Capriolo [mailto:edlinuxguru@gmail.com] 
> Sent: Sunday, November 11, 2012 9:37 AM
> To: user@cassandra.apache.org
> Subject: Re: CREATE COLUMNFAMILY
> 
> If you supply metadata cassandra can use it for several things.
> 
> 1) It validates data on insertion
> 2) Helps display the information in human readable formats in tools like the
> CLI and sstabletojson
> 3) If you add a built-in secondary index the type information is needed,
> strings sort differently then integer
> 4) columns in rows are sorted by the column name, strings sort differently
> then integers
> 
> On Sat, Nov 10, 2012 at 11:55 PM, Kevin Burton <rkevinburton@charter.net>
> wrote:
> 
> I am sure this has been asked before but what is the purpose of 
> entering key/value or more correctly key name/data type values on the 
> CREATE COLUMNFAMILY command.
> 
> 
> 
> 
>  


Mime
View raw message