title: How to Load CSV file into Apex 5 for particular columns?
body: <p>I have table  with three columns x (Foreign Key),y(Primary Key),z  and also csv file with  only two columns  data  y,z as shown in images <a href="http://imgur.com/a/12ENZ" rel="nofollow">http://imgur.com/a/12ENZ</a> (Please copy and paste link)which has to uploaded into table.Here I fill x column for all the rows with constant value ‘20’.i have used Data loading wizard to do this in Apex 5.
  Problem:
  In the first step I loaded this table and then In next step you can see that I have to do column mapping .Here I get only two columns y(Mileage),z(Ratio) because I have only two columns in the excel and first column x i  want to map with null values here(Problem 1).</p>
  
  <p>In the next step I have added process in the Datavalidation to update column x to fill that constant value as shown in images. But you could see p_attr_number =1 makes first column to be updated with 20 value.Here I need my first column x to be filled with constant value 20(Problem 2).Please Give me some suggestions on this for solving this problems.</p>