generate_create.rb

#!/usr/bin/env ruby

require 'json'
require 'optparse'

@file_path = ''
@separator = ''
@table_name = ''

OptionParser.new do |opts|
  opts.on('-f', '--file=file_path', 'fully qualified path to file')   {|file_path| @file_path = file_path}
  opts.on('-s', '--separator=separator', 'separator')                 {|separator| @separator = separator}
  opts.on('-t', '--table_name=table_name', 'name of final table')     {|table_name| @table_name = table_name}
end.parse!(ARGV)

# helpers
class String
  def is_integer?
     /\A[-+]?\d+\z/ === self
  end

  def is_number?
    true if Float(self) rescue false
  end
end

def infer_type(object)
  case
    when 
        begin 
          JSON.parse(object).is_a?(Hash)
        rescue => e
        end
      then 'variant'
    when object.is_number?
      then 'number'
    when object.is_integer?
      then 'integer'
    when (object.is_a?(TrueClass) || object.is_a?(FalseClass))
      then 'boolean'
    else 'varchar'
  end
end

def split_to_cols(line, separator)
  return line.split(separator)
end

def generate_create(table_name, column_names, data_types)
  "create table #{table_name} (#{column_names.zip(data_types).map{|pair| pair.join(' ')}.join(', ')});"
end

begin
  lines        = File.open(@file_path).map(&:strip).first(2)
  column_names = split_to_cols(lines[0], @separator)
  data_types   = split_to_cols(lines[1], @separator).map{|x| infer_type(x)}
  puts generate_create(@table_name, column_names, data_types)
rescue => e
end