Hadoop Beginner's Guide

Time for action – using a type mapping

Let's use a type mapping to improve our data import.

1. Delete any existing output directory:

   $ hadoop fs -rmr employees
   

2. Execute Sqoop with an explicit type mapping:

   sqoop import --connect jdbc:mysql://10.0.0.100/hadooptest --username hadoopuser 
   -P --table employees 
   --hive-import --hive-table employees 
   --map-column-hive start_date=timestamp
   

   You will receive the following response:

   12/05/23 14:53:38 INFO hive.HiveImport: Hive import complete.
   

3. Examine the created table definition:

   $ hive -e "describe employees"
   

   You will receive the following response:

   OK
   first_name  string  
   dept  string  
   salary  int  
   start_date  timestamp  
   Time taken: 2.547 seconds
   

4. Examine the imported data:

   $ hive -e "select * from employees"; ...