def null_value
      match = /((\w*) NULL)/i.match(definition)
      return true unless match

      match[2].downcase == 'not' ? false : true
    end
def null_value
      match = /((\w*) NULL)/i.match(definition)
      return true unless match

      match[2].downcase == 'not' ? false : true
    end
Checks whether the column accepts NULL as specified in the definition

 @return [Boolean]