更改猪模式

Question

我正在尝试更改架构：

describe JOINED_WITH_PARENT;
JOINED_WITH_PARENT: {ROWS_TUPLES::id: chararray,ROWS_TUPLES::url: chararray,ROWS_TUPLES::score: chararray,ROWS_TUPLES::parentId: chararray,ROWS_TUPLES::title: chararray,ROWS_TUPLES::body: chararray,GROUPED_PARENT_ID::group: chararray,GROUPED_PARENT_ID::ROWS_TUPLES: {(id: chararray,url: chararray,score: chararray,parentId: chararray,title: chararray,body: chararray)}}

收件人：

JOINED_WITH_PARENT: {id: chararray,url: chararray,:score: parentId: chararray,title: chararray,body: chararray,group: chararray, answers: {(id: chararray,url: chararray,score: chararray,parentId: chararray,title: chararray,body: chararray)}}

我正在考虑在 JOINED_WITH_PARENT 上执行 foreach 并尝试了以下内容，但语法似乎不正确。我在正确的轨道上吗？任何帮助将不胜感激

A = FOREACH JOINED_WITH_PARENT GENERATE 
   id as (id:chararray),
   score as (score:chararray),
   parentId as (parentId:chararray),
   title as (title:chararray),
   body as (body:chararray),
   group as (group:chararray),
   answers as tuple(chararray,chararray,chararray,chararray,chararray)GROUPED_PARENT_ID::ROWS_TUPLES;

Answer 1

如果您只想投影字段，则不应指定类型，并且当您从联接投影时需要指定 "source" 关系，如下所示：

A = FOREACH JOINED_WITH_PARENT GENERATE 
   ROWS_TUPLES::id as id,
   ROWS_TUPLES::score as score,
   ...
   GROUPED_PARENT_ID::ROWS_TUPLES as answers;

更改猪模式

Change pig schema

apache-pig