Sqoop is very helpful in importing data from RDBMS to hadoop. The hive import feature will create a hive table corresponding to the RDBMS table and import the data. By default sqoop creates a hive table based on the predefined data type conversion logic build inside sqoop. We have an option to change the default conversion. We can explicitly specify the data type required in the hive table. This is possible by adding an extra option as below.
--map-column-java <mapping> Override mapping from SQL to Java type for configured columns. --map-column-hive <mapping> Override mapping from SQL to Hive type for configured columns.
For example. If we have a field called ‘id‘ in an sql table which is of integer data type and we want it as a string data type column in hive, we can do the following step.
sqoop import ... --map-column-hive id=string