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From aaron morton <aa...@thelastpickle.com>
Subject Re: CF metadata syntax for an array
Date Wed, 14 Nov 2012 04:18:16 GMT
> Would this syntax be the same for CREATE COLUMNFAMILY (as an aside what is a ‘TABLE’
in Cassandra)?
Yes, CQL 2 uses COLUMN FAMILY or Table and CQL 3 uses TABLE

http://www.datastax.com/dev/blog/cql3-evolutions

> In other words is this valid:
Does it work ? Is so it's valid. 

> Does the  array have to be a KEY?
Sorry I don't understand this question. 

> Finally, what would be the syntax for inserting data into the CF?
Depends on what you want to do.
Docs are a good starting point http://www.datastax.com/docs/1.1/references/cql/index

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 14/11/2012, at 2:42 AM, Kevin Burton <rkevinburton@charter.net> wrote:

> Sorry to be so slow but I am just learning CQL. Would this syntax be the same for CREATE
COLUMNFAMILY (as an aside what is a ‘TABLE’ in Cassandra)? In other words is this valid:
>  
>                         CREATE COLUMNFAMILY Description (
>                                                        PRIMARY_KEY (vector_name, index),
>                                                        Age text,
>                                                        Gender text,
>                                                       vector_name text,
>                                                       index bigint,
> …..
>  
> Or
>                         CREATE COLUMNFAMILY Description (
>                                                        PRIMARY_KEY (listr_name, sort_key),
>                                                        Age text,
>                                                        Gender text,
>                                                        sort_key bigint,
>                                                       list_name text
> ….
> 
> Does the  array have to be a KEY? Finally, what would be the syntax for inserting data
into the CF?
>  
> Thanks again.
>  
> From: aaron morton [mailto:aaron@thelastpickle.com] 
> Sent: Tuesday, November 13, 2012 4:09 AM
> To: user@cassandra.apache.org
> Subject: Re: CF metadata syntax for an array
>  
> While this solves the problem for an array of 'primitive' types. What if I want an array
or collection of an arbitrary type like list<foo>, where foo is a user defined type?
> Do you mean a custom Cassandra data type that sub classes AbstractType? I dont think
CQL can support those, I may be wrong though. 
>  
> If you mean a basic client side data type you could serialise it and store as a string
or byte buffer in a CQL collection. 
>  
> What are the options to solve this type of array? 
> ...
> 
> arbitrary type like list<foo>, 
> Do you mean an array such as int[] or do you mean the equivalent of a java List<T>
with functions like remove that actually delete items and from the list?
>  
> If it's the former a CQL table such as below would work
>  
> CREATE TABLE vectors (
>             vector_name text,
>             index bigint,
>             object_property_1 text,
>             object_property_2 text,
>             PRIMARY_KEY (vector_name, index)
> );
>  
> The problem is, if you delete a element at (vector, index) the remaining indexes will
be off.
>  
> If it's the later, a List<T>, then it depends a little on what features you want
to support. If you want a sorted list of objects the table is roughly the same
>  
> CREATE TABLE List (
>             list_name text,
>             sort_key bigint,
>             object_property_1 text,
>             object_property_2 text,
>             PRIMARY_KEY (list_name, sort_key)
> );
>  
> Hope that helps. 
>  
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>  
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>  
> On 13/11/2012, at 9:46 AM, Kevin Burton <rkevinburton@charter.net> wrote:
> 
> 
> While this solves the problem for an array of 'primitive' types. What if I want an array
or collection of an arbitrary type like list<foo>, where foo is a user defined type?
I am guessing that this cannot be done with 'collections'. What are the options to solve this
type of array?
> 
> On Nov 12, 2012, at 2:28 PM, aaron morton <aaron@thelastpickle.com> wrote:
> 
> This may help http://www.datastax.com/dev/blog/cql3_collections
>  
>  I have gotten as far as feeling a need to understand a ‘super-column’ 
> You can happily ignore them.
>  
>  
> Cheers
>  
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>  
> On 12/11/2012, at 8:35 PM, Kevin Burton <rkevinburton@charter.net> wrote:
> 
> 
> I am sorry if this is an FAQ. But I was wondering what the syntax for describing an array?
I have gotten as far as feeling a need to understand a ‘super-column’ but I fail after
that. Once I have the metadata in place to describe an array how do I  insert data into the
array? Get data from the array? Thank you.
>  
>  


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