title: Column names return lowercase in aws glue
body: <p>I am new to AWS Glue, and have created job through crawler which point the source target CSV-file in S3-bucket.</p>
  
  <p>The CSV-file contains following columns as:</p>
  
  <pre><code>userId  jobTitleName    firstName   lastName    preferredFullName   employeeCode    region
  </code></pre>
  
  <p>Now during the job execution, it throws following error
  <code>Key error: userid' not exist</code>. As notified, the issue looks the case sensitive issue. so as per the glue-document, I created mapping for the schema</p>
  
  
  
  <pre><code>mappingsSchema=[('userid', 'integer', 'userId', 'integer'),
                   ('jobtitlename', 'string', 'jobTitleName', 'string'),
                   ('firstname', 'string', 'firstName', 'string'),
                   ('lastname', 'string', 'lastName', 'string'),
                   ('preferredfullName', 'string', 'preferredFullname', 'string'),
                   ('employeecode', 'string', 'employeeCode', 'string'),
                   ('region', 'string','region', 'string')]
  mapped_dynamic_frame_read=dynamic_frame_read.apply_mapping(mappings = mappingsSchema, case_sensitive = True, transformation_ctx = "tfx")
  ##And converting to the spark df
  df = mapped_dynamic_frame_read.toDF()
  </code></pre>
  
  <p>Still I'mm getting the same mentioned error. 
  How can resolve this kind of issue?</p>