title: Explanation of Django Table Relations and How they are Being Called
body: <p>I'm fairly new to Django and am currently trying to go through and modify a preexisting website. I'm trying to understand the syntax involved with creating a chart based on certain parameters. Currently the site takes account types as an argument and spits out a plot of account values vs. years. As shown in the first picture: 
  <a href="https://i.stack.imgur.com/BUmcb.png" rel="nofollow noreferrer">Picture of Plot</a></p>
  
  <p>The part of the code I'm confused about is here: </p>
  
  <pre><code>tag_ids = [56, 123, 15, 21, 82]
  if categories_1:
      tag_ids = categories_1.split(',')
  
  tags = []
  
  
  funding_announced_min = minyear+'-01-01'
  funding_announced_max = maxyear+'-12-31'
  
  business_list = []
  for d in tag_ids:
      tag1 = Tag_objs.objects.get(pk=int(d))
      tags.append(tag1)
      business_1 = tag1.buisiness.filter(
          company__founded_date__gte=funding_announced_min,
          company__founded_date__lte=funding_announced_max,
          entity_type=0,
          )
      business_list.append(business1)
  </code></pre>
  
  <p><code>tag</code> is a table of account types, and my confusion comes from the b<code>usiness_1 = tag1.business.filter</code> section. What exactly is this doing? </p>
  
  <p>I have a model called <code>biz</code> that looks like this: </p>
  
  <pre><code>class biz(Ent):  
  founded_date = models.DateField(blank=True, null=True)
  employee_amount = models.IntegerField('Number of Employees',blank=True, null=True)
  employee_amount_range = models.CharField(max_length=64, blank=True, null=True)
  biz_status = models.CharField(choices=BIZ_STATUS_CHOICES, max_length=32, default='operating', blank=True, null=True)
  zipcode = models.CharField(max_length=64, blank=True, null=True)
  address = models.CharField(max_length=255, blank=True, null=True)
  funding_rounds = models.IntegerField(default=0, blank=True, null=True)
  funding_total_usd = models.BigIntegerField(default=0, blank=True, null=True)
  first_funding_on = models.DateField(blank=True, null=True)
  last_funding_on = models.DateField(blank=True, null=True)
  closed_on = models.DateField(blank=True, null=True)
  employee_count_min = models.IntegerField(default=0, blank=True, null=True)
  employee_count_max = models.IntegerField(default=0, blank=True, null=True)
  
  def __str__(self):  
      return self.name
  
  class Meta:
      verbose_name_plural = "business"
  </code></pre>
  
  <p>But the only instance where I can see <code>business</code> is being referenced by a model is here in the <code>verbose_name_plural</code>. Does <code>verbose_name_plural</code> mean I can call the table <code>biz</code> as "business"?. The <code>ent</code> class is here:</p>
  
  <pre><code>class Ent(models.Model):
  name = models.CharField('Name', max_length=255, db_index=True) 
  desc = models.TextField('Description')
  image = models.ImageField('Logo Image', upload_to='biz', blank=True, null=True, default='biz/default-user110.jpg')
  cover_image = models.ImageField('Cover Image', upload_to='biz', blank=True, null=True, help_text='1300 width by 300 height top cover image.')
  tags = models.ManyToManyField(Tag,related_name='business', blank=True)
  featured = models.BooleanField()
  limited = models.BooleanField()
  city = models.CharField(max_length=128) 
  state_province = models.CharField(max_length=128, blank=True, null=True) 
  region = models.CharField(max_length=128, blank=True, null=True) 
  country = models.CharField(choices=COUNTRY_CHOICES, max_length=128)
  entity_type = models.IntegerField(choices=ENTITY_TYPE_CHOICES)
  elevator_pitch = models.CharField(max_length=64, blank=True, null=True)
  logo_url = models.URLField(max_length=255, blank=True, null=True)
  profile_image_url = models.URLField(max_length=255, blank=True, null=True)
  primary_role = models.CharField(max_length=32, blank=True, null=True)
  uuid = models.CharField(max_length=128, blank=True, null=True, unique=True)
  domain = models.CharField(max_length=255, blank=True, null=True)
  slug = models.SlugField(max_length=255, blank=True, null=True, unique=True)
  created_at = models.DateTimeField(auto_now_add = True)
  updated_at = models.DateTimeField(auto_now = True)
  
  def __str__(self):  
      return self.name
  
  def get_absolute_url(self):
  
      try:
          int(self.slug[-1:])
          if self.slug.replace('-', ' ').lower() == self.name.lower():
              return reverse('business:biz', kwargs={'slug':slugify(self.name)})
          self.slug=slugify(self.name+' '+str(self.pk))
          return reverse('business:biz', kwargs={'slug':slugify(self.name+' '+str(self.pk))})
      except ValueError:
          self.slug=slugify(self.name)
          return reverse('business:biz', kwargs={'slug':slugify(self.name)})
  </code></pre>
  
  <p>To my understanding the class <code>biz</code> is a type of the class <code>ent</code> and the line <code>business.filter</code> is sorting through the <code>ent</code> table that is created by the <code>ent</code> model. If someone could give me a brief explanation of the line in question and then how the tables are communicating I'd be super appreciative. I apologize if this is a little confusing, I'm new and this is my first post. I couldn't find anything else like it in previous searches.</p>