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Pig, mail # user - define global constants in pig script


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Re: define global constants in pig script
Haitao Yao 2012-07-30, 06:38
Yes, this is just what I'm looking for.
thanks.

Haitao Yao
[EMAIL PROTECTED]
weibo: @haitao_yao
Skype:  haitao.yao.final

在 2012-7-27,下午5:26, Jonathan Coveney 写道:

> Pig already has this! :)
> http://pig.apache.org/docs/r0.10.0/cont.html#parameter-sub
>
> Unless I'm really misunderstanding what you mean?
>
> 2012/7/26 Haitao Yao <[EMAIL PROTECTED]>
>
>> Hi, all
>>        I got an idea about a new feature for pig: define global constants
>> in pig script.
>>        Here's the example like this:
>>
>> -- define a global constant for storage
>> define store_location "/where_you_store_result";
>>
>> -- then all the following constants reference will be replaced in runtime
>> store Result into $$store_location using PigStorage(',');
>>
>>
>>        so, in this way, we just write the template scripts and import
>> them with the constants defined. A commonly use case is use it to compute
>> data for different days.
>>        Without this feature, I have to use sed to replace the variables
>> on the template script to generate the daily pig scripts.
>>        How do you guy think so?
>>
>>
>> Haitao Yao
>> [EMAIL PROTECTED]
>> weibo: @haitao_yao
>> Skype:  haitao.yao.final
>>
>>