Apache Pig Describe operator

The describe operator is used to view the pattern of the relationship.

Grammar

The syntax of the describe operator is as follows

grunt> Describe Relation_name

Cases

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 describe the relationship called student and verify the pattern as follows.

grunt> describe student;

Output

After executing the Pig Latin statement above, the following output is generated.

grunt> student: { id: int,firstname: chararray,lastname: chararray,phone: chararray,city: chararray }