incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Kevin Burton" <rkevinbur...@charter.net>
Subject RE: CREATE COLUMNFAMILY
Date Sun, 11 Nov 2012 22:09:32 GMT
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