old_contents: from django.db import models
  from django.utils import timezone
  
  class NLRequest(models.Model):
      request_str = models.TextField()
  
      # used to display a list of query suggestions in the main page
      sub_time = models.DateTimeField(default=timezone.now)
      frequency = models.PositiveIntegerField(default=0)
  
      def __str__(self):
          return self.request_str
  
  
  class Translation(models.Model):
      request = models.ForeignKey(NLRequest, on_delete=models.CASCADE)
      pred_cmd = models.TextField()
      score = models.FloatField()
      num_votes = models.PositiveIntegerField(default=0)
  
      def __str__(self):
          return "{}\n{}".format(self.request, self.pred_CMD)
new_contents: from django.db import models
  from django.utils import timezone
  
  class NLRequest(models.Model):
      request_str = models.TextField()
  
      # used to display a list of query suggestions in the main page
      sub_time = models.DateTimeField(default=timezone.now)
      frequency = models.PositiveIntegerField(default=0)
  
      def __str__(self):
          return self.request_str
  
  
  class Translation(models.Model):
      request = models.ForeignKey(NLRequest, on_delete=models.CASCADE)
      pred_cmd = models.TextField()
      score = models.FloatField()
      num_votes = models.PositiveIntegerField(default=0)
  
      def __str__(self):
          return "{}\n{}".format(self.request, self.pred_cmd)
  
subject: fix database field name bug