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From Dalia Sobhy <dalia.mohso...@hotmail.com>
Subject Re: Question
Date Tue, 13 Nov 2012 22:14:05 GMT
Hello Ted:

I have a patient table which contains two column families: info and cardiac.

I need to count the number of people who suffer from a particular diagnosis within cardiac.

For instance the number of patients suffering from "heart failure"

Sent from my iPad

On Nov 13, 2012, at 11:00 PM, "Ted Yu" <yuzhihong@gmail.com> wrote:

> Currently http://hbase.apache.org/book.html gives me networks error.
> You should be able to find example of how Java client connects to HBase cluster.
> 
> How ColumnInterpreter is initialized depends on your schema. Can you tell us more about
your schema ?
> 
> Thanks
> 
> On Tue, Nov 13, 2012 at 12:40 PM, Dalia Sobhy <dalia.mohsobhy@hotmail.com> wrote:
>> 
>> 
>> 
>> 
>> Begin forwarded message:
>> 
>>> From: Dalia Sobhy <dalia.mohsobhy@hotmail.com>
>>> Date: November 12, 2012, 10:12:57 PM GMT+02:00
>>> To: <yuzhihong@gmail.com>
>>> Subject: RE: Question
>>> 
>>> Thanks,
>>> 
>>> But how to initialize the ColumnInterpreter, I mean how to link it with a table.
>>> 
>>> Another aspect, its my first time to use java classes for hbase, I was using
thrift server to connect to hbase. But due to the need for aggregate functions i shifted to
hbase 0.92.
>>> 
>>> So could you explain to me in brief how are the java classes connected to hbase
server.
>>> 
>>> Thanks in advance :D
>>> 
>>> Date: Mon, 12 Nov 2012 11:35:58 -0800
>>> 
>>> Subject: Re: Question
>>> From: yuzhihong@gmail.com
>>> To: dalia.mohsobhy@hotmail.com
>>> CC: user@hbase.apache.org
>>> 
>>> 
>>> double is primitive type.
>>> Replace with Double.
>>> 
>>> Cheers
>>> 
>>> On Mon, Nov 12, 2012 at 11:31 AM, Dalia Sobhy <dalia.mohsobhy@hotmail.com>
wrote:
>>> 
>>> 
>>> Syntax error on token "double", Dimensions expected after this token
>>> 
>>> Pastebin link:
>>> http://pastebin.com/dcvaMvLw
>>> 
>>> I am trying to send it on the group but I dunno why hotmail disagrees and sends
me postmaster failure so weird!!!
>>> 
>>> 
>>> > CC: user@hbase.apache.org
>>> > From: yuzhihong@gmail.com
>>> > Subject: Re: Question
>>> > Date: Sun, 11 Nov 2012 12:31:16 -0800
>>> > To: user@hbase.apache.org
>>> 
>>> > 
>>> > What error did you get ?
>>> > Please use pastebin to share. 
>>> > 
>>> > Thanks
>>> > 
>>> > 
>>> > 
>>> > On Nov 11, 2012, at 11:42 AM, Dalia Sobhy <dalia.mohsobhy@hotmail.com>
wrote:
>>> > 
>>> > > 
>>> > > Hi Ted,
>>> > > 
>>> > > I am using hbase 0.92.1
>>> > > 
>>> > > When I tried the following code I got errors:
>>> > > 
>>> > > AggregateProtocol agg; 
>>> > > long rowcount = agg.getRowNum(ColumnInterpreter<string, int>,
scan);
>>> > > 
>>> > > double sum = aggregationClient.avg(TABLE_NAME, ci, scan);
>>> > > 
>>> > > even though I tried it with String (s in capital) same errors, do u
know why?
>>> > > 
>>> > >> Date: Sun, 11 Nov 2012 08:24:29 -0800
>>> > >> Subject: Re: Question
>>> > >> From: yuzhihong@gmail.com
>>> > >> To: user@hbase.apache.org
>>> > >> 
>>> > >> Dalia:
>>> > >> If you look at:
>>> > >> public interface ColumnInterpreter<T, S> {
>>> > >> 
>>> > >> you would see:
>>> > >> * @param <T> Cell value data type
>>> > >> * @param <S> Promoted data type
>>> > >> 
>>> > >> S can represent sum of values of T. The rationale was that aggregation
of
>>> > >> one type (integer, e.g.) may have to be represented by another
type
>>> > >> (double, e.g.)
>>> > >> 
>>> > >> From this blog you can get some history on this subject:
>>> > >> http://zhihongyu.blogspot.com/2011/03/genericizing-endpointcoprocessor.html
>>> > >> 
>>> > >> For row counting, it is already implemented:
>>> > >> public <T, S> long getRowNum(ColumnInterpreter<T, S>
ci, Scan scan)
>>> > >> You can embed your filter in scan object.
>>> > >> 
>>> > >> Cheers
>>> > >> 
>>> > >> On Sun, Nov 11, 2012 at 8:07 AM, Dalia Sobhy <dalia.mohsobhy@hotmail.com>wrote:
>>> > >> 
>>> > >>> 
>>> > >>> 
>>> > >>> Thanks Ted :D
>>> > >>> 
>>> > >>> But can anyone explain to me this sentence:
>>> > >>> 
>>> > >>> ColumnInterpreter<T, S> ci
>>> > >>> 
>>> > >>> How to set a ColumnInterpreter ?? What is T and Whats S?
>>> > >>> 
>>> > >>> I want to perform average on an Aggregationclient, so could
anyone provide
>>> > >>> me with a sample code?
>>> > >>> 
>>> > >>> Also if i want to count the number of rows which has a specific
value ?
>>> > >>> What to use Filters or AggregationClient?
>>> > >>> 
>>> > >>> Thanks in advance,
>>> > >>> 
>>> > >>>> Date: Sat, 10 Nov 2012 14:25:22 -0800
>>> > >>>> Subject: Re: Question
>>> > >>>> From: yuzhihong@gmail.com
>>> > >>>> To: user@hbase.apache.org
>>> > >>>> 
>>> > >>>> Take a look at AggregationClient.java and TestAggregateProtocol.java
>>> > >>>> 
>>> > >>>> Cheers
>>> > >>>> 
>>> > >>>> On Sat, Nov 10, 2012 at 2:11 PM, Dalia Sobhy <dalia.mohsobhy@hotmail.com
>>> > >>>> wrote:
>>> > >>>> 
>>> > >>>>> 
>>> > >>>>> Dear all,
>>> > >>>>> 
>>> > >>>>> I want to use the aggregate functions, but do anyone
have a code or
>>> > >>> sth to
>>> > >>>>> understand them ..
>>> > >>>>> 
>>> > >>>>> Thanks
>>> > >>>>> 
>>> > >>>>> Best Regards
>>> > >>>>> Dalia
>>> > >>>>> 
>>> > >>> 
>>> > >>> 
>>> > >
> 

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