title: django composite key data fetch
body: <p>I have two tables dim_job and dim_stream when i do python manage.py inspectdb > models.py.......... then below shown models.py(class shown) is created in  django........
  dim_job table has three attributes where job_name and alias combined as primary key......here alias is also a foreign key referencing dim_stream table alias.
  dim_stream table has two attributes where alias is primary key...........
  When i try to execute DimJob.objects.all() shows error.?
  How can data be fetched from dim_job table?django queries?</p>
  
  <p>In error i see that dim_job.id doesn't exist ....I don't understand why it is showing this?Already there is combined primary key(job_name,alias) .</p>
  
  <p>I am using postgres database </p>
  
  <pre><code>    class DimJob(models.Model):
            job_name = models.CharField(max_length=50)
            alias = models.ForeignKey('DimStream', db_column='alias')
            job_start_time = models.CharField(max_length=20, blank=True, null=True)
  
            class Meta:
                managed = False
                db_table = 'dim_job'
                unique_together = (('job_name', 'alias'),)
  
  
  
      class DimStream(models.Model):
            stream_name = models.CharField(max_length=50, blank=True, null=True)
            alias = models.CharField(primary_key=True, max_length=50)
  
            class Meta:
                managed = False
                db_table = 'dim_stream'
  
            def __str__(self):
                return self.stream_name
  
  
  
  
           Error:
             DimJob.objects.all()
             Traceback (most recent call last):
             File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
             32\lib\site-packages\django\core\management\commands\shell.py", 
             line 69, in handle
             self.run_shell(shell=options['interface'])
             File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
             32\lib\site-packages\django\core\management\commands\shell.py", 
             line 61, in run_shell
             raise ImportError
             ImportError
  
             During handling of the above exception, another exception 
             occurred:
  
             Traceback (most recent call last):
             File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
             32\lib\site-packages\django\db\backends\utils.py", line 64, in 
             execute
             return self.cursor.execute(sql, params)
             psycopg2.ProgrammingError: column dim_job.id does not exist
             LINE 1: SELECT "dim_job"."id", "dim_job"."job_name", 
             "dim_job"."alia...
             ^
  
  
                The above exception was the direct cause of the following 
                exception:
  
                Traceback (most recent call last):
                File "&lt;console&gt;", line 1, in &lt;module&gt;
                File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
                32\lib\site-packages\django\db\models\query.py", line 138, in 
                 __repr__
                data = list(self[:REPR_OUTPUT_SIZE + 1])
                File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
                32\lib\site-packages\django\db\models\query.py", line 162, in 
               __iter__
               self._fetch_all()
                File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
                 32\lib\site-packages\django\db\models\query.py", line 965, in 
                 _fetch_all
               self._result_cache = list(self.iterator())
               File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
               32\lib\site-packages\django\db\models\query.py", line 238, in 
                iterator
              results = compiler.execute_sql()
               File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
               32\lib\site-packages\django\db\models\sql\compiler.py", line 
              829, in execute_sql
              cursor.execute(sql, params)
              File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
               32\lib\site-packages\django\db\backends\utils.py", line 79, in 
             execute
            return super(CursorDebugWrapper, self).execute(sql, params)
            File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
            32\lib\site-packages\django\db\backends\utils.py", line 64, in 
          execute
            return self.cursor.execute(sql, params)
             File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
           32\lib\site-packages\django\db\utils.py", line 97, in __exit__
          six.reraise(dj_exc_type, dj_exc_value, traceback)
           File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
         32\lib\site-packages\django\utils\six.py", line 658, in reraise
           raise value.with_traceback(tb)
           File "C:\Users\vivekre\AppData\Local\Programs\Python\Python36- 
          32\lib\site-packages\django\db\backends\utils.py", line 64, in 
          execute
            return self.cursor.execute(sql, params)
         django.db.utils.ProgrammingError: column dim_job.id does not exist
         LINE 1: SELECT "dim_job"."id", "dim_job"."job_name", 
         "dim_job"."alia...
  </code></pre>