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From Miguel Angel Martin junquera <mianmarjun.mailingl...@gmail.com>
Subject Re: how can i get the column value? Need help!.. cassandra 1.28 and pig 0.11.1
Date Wed, 28 Aug 2013 08:02:54 GMT
hi:

I can not understand why the schema is  define like
*"id:chararray,age:int,title:chararray"
 and it does not define like tuples or bag tuples,  if we have pair
key-values  columns*
*
*
*
*
*I try other time to change schema  but it does not work.*
*
*
*any ideas ...*
*
*
*perhaps, is the issue in the definition cql3 tables ?*
*
*
*regards*


2013/8/28 Miguel Angel Martin junquera <mianmarjun.mailinglist@gmail.com>

> hi all:
>
>
> Regards
>
> Still i can resolve this issue. .....
>
> does anybody have this issue or try to test this simple example?
>
>
> i am stumped I can not find a solution working.
>
> I appreciate any comment or help
>
>
> 2013/8/22 Miguel Angel Martin junquera <mianmarjun.mailinglist@gmail.com>
>
>> hi all:
>>
>>
>>
>>
>> I,m testing the new CqlStorage() with cassandra 1.28 and pig 0.11.1
>>
>>
>> I am using this sample data test:
>>
>>
>> http://frommyworkshop.blogspot.com.es/2013/07/hadoop-map-reduce-with-cassandra.html
>>
>> And I load and dump data Righ with this script:
>>
>> *rows = LOAD
>> 'cql://keyspace1/test?page_size=1&split_size=4&where_clause=age%3D30' USING
>> CqlStorage();*
>> *
>> *
>> *dump rows;*
>> *describe rows;*
>> *
>> *
>>
>> *resutls:
>>
>> ((id,6),(age,30),(title,QA))
>>
>> ((id,5),(age,30),(title,QA))
>>
>> rows: {id: chararray,age: int,title: chararray}
>>
>>
>> *
>>
>>
>> But i can not  get  the column values
>>
>> I try to define   another schemas in Load like I used with
>> cassandraStorage()
>>
>>
>> http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Cassandra-and-Pig-how-to-get-column-values-td5641158.html
>>
>>
>> example:
>>
>> *rows = LOAD
>> 'cql://keyspace1/test?page_size=1&split_size=4&where_clause=age%3D30' USING
>> CqlStorage() AS (columns: bag {T: tuple(name, value)});*
>>
>>
>> and I get this error:
>>
>> *2013-08-22 12:24:45,426 [main] ERROR org.apache.pig.tools.grunt.Grunt -
>> ERROR 1031: Incompatable schema: left is
>> "columns:bag{T:tuple(name:bytearray,value:bytearray)}", right is
>> "id:chararray,age:int,title:chararray"*
>>
>>
>>
>>
>> I try to use, FLATTEN, SUBSTRING, SPLIT UDF`s but i have not get good
>> result:
>>
>> Example:
>>
>>
>>    - when I flatten , I get a set of tuples like
>>
>> *(title,QA)*
>>
>> *(title,QA)*
>>
>> *2013-08-22 12:42:20,673 [main] INFO
>>  org.apache.pig.backend.hadoop.executionengine.util.MapRedUtil - Total
>> input paths to process : 1*
>>
>> *A: {title: chararray}*
>>
>>
>>
>> but i can get value QA
>>
>> Sustring only works with title
>>
>>
>>
>> example:
>>
>> *B = FOREACH A GENERATE SUBSTRING(title,2,5);*
>> *
>> *
>> *dump B;*
>> *describe B;*
>> *
>> *
>> *
>> *
>>
>> *results:*
>> *
>> *
>>
>> *(tle)*
>> *(tle)*
>> *B: {chararray}*
>>
>>
>>
>>
>> i try, this like ERIC LEE inthe other mail  and have the same results:
>>
>>
>>  Anyways, what I really what is the column value, not the name. Is there
>> a way to do that? I listed all of the failed attempts I made below.
>>
>>    - colnames = FOREACH cols GENERATE $1 and was told $1 was out of
>>    bounds.
>>    - casted = FOREACH cols GENERATE (tuple(chararray, chararray))$0; but
>>    all I got back were empty tuples
>>    - values = FOREACH cols GENERATE $0.$1; but I got an error telling me
>>    data byte array can't be casted to tuple
>>
>>
>> Please, I will appreciate any help
>>
>>
>> Regards
>>
>>
>>
>>
>>
>>
>>
>
>
> --
>
> Miguel Angel Martín Junquera
> Analyst Engineer.
> miguelangel.martin@brainsins.com
> Tel. / Fax: (+34) 91 485 56 66
> *http://www.brainsins.com*
> Smart eCommerce
> *Madrid*: http://goo.gl/4B5kv
>  *London*: http://goo.gl/uIXdv
>  *Barcelona*: http://goo.gl/NZslW
>
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>



-- 

Miguel Angel Martín Junquera
Analyst Engineer.
miguelangel.martin@brainsins.com

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