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The illustrate operator gives you the step-by-step execution of a sequence of statements.
Syntax
Given below is the syntax of the illustrate operator.
grunt> illustrate Relation_name;
Example
Assume we have a file student_data.txt in HDFS with the following content.
001,Rajiv,Reddy,9848022337,Hyderabad 002,siddarth,Battacharya,9848022338,Kolkata 003,Rajesh,Khanna,9848022339,Delhi 004,Preethi,Agarwal,9848022330,Pune 005,Trupthi,Mohanthy,9848022336,Bhuwaneshwar 006,Archana,Mishra,9848022335,Chennai.
And we have read it into a relation student using the LOAD operator as shown below.
grunt> student = LOAD ''hdfs://localhost:9000/pig_data/student_data.txt'' USING PigStorage('','') as ( id:int, firstname:chararray, lastname:chararray, phone:chararray, city:chararray );
Now, let us illustrate the relation named student as shown below.
grunt> illustrate student;
Output
On executing the above statement, you will get the following output.
grunt> illustrate student; INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapOnly$M ap - Aliases being processed per job phase (AliasName[line,offset]): M: student[1,10] C: R: --------------------------------------------------------------------------------------------- |student | id:int | firstname:chararray | lastname:chararray | phone:chararray | city:chararray | --------------------------------------------------------------------------------------------- | | 002 | siddarth | Battacharya | 9848022338 | Kolkata | ---------------------------------------------------------------------------------------------
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