May 26, 2021 Apache Pig
The play operator gives you step-by-step execution of a series of statements.
The syntax of the indicator operator is given below.
grunt> illustrate Relation_name;
Suppose you have a file in HDFS that contains the following student_data.txt.
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.
Use the LOAD operator to read it into the relationship student, 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's explain the relationship called student as shown below.
grunt> illustrate student;
When you execute the above statement, you 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 | ---------------------------------------------------------------------------------------------