Django 3.2 - raw-SQL-Query with same table (Model) - django

Question

We have migrated some database-tables from our productiv environment to the django ORM and auto sync this tables outside of django. → This works well so far, but we have troubles in django to connect this tables (Models) correctly to each other.
models.py
class SsdaSdgadr(models.Model):
sda_sdgid = models.ForeignKey(SsdgSendung, on_delete=models.CASCADE, blank=True, null=True)
sda_satid = models.CharField(max_length=4, blank=True, null=True)
sda_adrid = models.ForeignKey(SadrAdresse, on_delete=models.CASCADE, blank=True, null=True)
sda_ref = models.CharField(max_length=35, blank=True, null=True)
sda_termbis = models.DateField(blank=True, null=True)
sda_termvon = models.DateField(blank=True, null=True)
class Meta:
db_table = 'ssda_sdgadr'
unique_together = (('sda_sdgid', 'sda_satid'),)
class SsdgSendung(models.Model):
sdg_sdgid = models.CharField(primary_key=True, max_length=30)
sdg_konz = models.CharField(max_length=12, blank=True, null=True)
class Meta:
db_table = 'ssdg_sendung'
class SadrAdresse(models.Model):
adr_adrid = models.IntegerField(primary_key=True)
adr_name1 = models.CharField(max_length=35, blank=True, null=True)
adr_name2 = models.CharField(max_length=35, blank=True, null=True)
class Meta:
db_table = 'sadr_adresse'
Sample Data
SsdaSdgadr:
sdg_sdgid
sda_satid
sda_adrid
sda_ref
sda_termvon
sda_termbis
BL-1237781-BL-1
IV
169550
'00123/4539999'
''
''
BL-1237781-BL-1
SU
555555
''
01.12.2021
02.12.2021
BL-1237781-BL-1
CN
999999
'00123'
02.12.2021
13.12.2021
views.py
I used following raw SQL
Sendungen = SsdaSdgadr.objects.raw('''
SELECT
IV.id,
IV.sda_sdgid_id,
IV.sda_ref,
SU.id,
SU.sda_adrid_id as ABS,
SU.sda_termvon,
CN.id,
CN.sda_adrid_id as EMPF,
CN.sda_termbis
FROM
ssda_sdgadr IV
INNER JOIN ssdg_sendung on sdg_sdgid = IV.sda_sdgid_id
INNER JOIN ssda_sdgadr SU on SU.sda_sdgid_id = IV.sda_sdgid_id and SU.sda_satid="SU"
INNER JOIN ssda_sdgadr CN on CN.sda_sdgid_id = IV.sda_sdgid_id and CN.sda_satid="CN"
WHERE IV.sda_satid="IV"
GROUP BY
IV.id,
IV.sda_sdgid_id,
IV.sda_ref,
SU.id,
SU.sda_adrid_id,
SU.sda_termvon,
CN.id,
CN.sda_adrid_id,
CN.sda_termbis
ORDER BY
sdg_datum desc
''')
...
response = render(request, 'cust/home.html', {
'Sendungen': Sendungen,
})
return response
The result on the template works fine for the fields "SU.sda_termvon" & "CN.sda_termbis", but does not work for the field "sda_adrid" (→ Only the the result for IV.sda_adrid_id is displayed).
Template code
{% for la_item in Sendungen %}
<tr>
<td>{{ la_item.sda_sdgid.sdg_sdgid }}</td>
<td>{{ la_item.sda_ref }}</td> <!-- IV.sda_ref OKAY -->
<td>{{ la_item.sda_adrid.adr_adrid }}</td> <!-- is IV.sda_adrid NOT OKAY -->
<td>{{ la_item.sda_adrid.adr_adrid }}</td> <!-- is IV.sda_adrid NOT OKAY -->
<td>{{ la_item.sda_termvon|date }}</td> <!-- SU.sda_termvon OKAY -->
<td>{{ la_item.sda_termbis|date }}</td> <!-- CN.sda_termbis OKAY -->
</tr>
{% endfor %}
How can I access to the results "CN.sda_adrid_id" & "SU.sda_adrid_id" on template?
→ It look like that the ORM interprets the raw-SQL different than the database:
DB-Result & Desired result should look like this:
sda_sdgid_id
IV.sda_ref
SU.sda_adrid_id
CN.sda_adrid
SU.termvon
CN.termbis
BL-1237781-BL-1
1920192/4530210220/0881760357
555555
999999
01.12.2021
13.12.2021
My actual result look like this:
sda_sdgid_id
IV.sda_ref
IV.sda_adrid_id
IV.sda_adrid_id
SU.termvon
CN.termbis
BL-1237781-BL-1
1920192/4530210220/0881760357
169550
169550
01.12.2021
13.12.2021

Answer 1

I used this workaround (model property for "SsdaSdgadr"), which gave me the desired result:
models.py
class SsdaSdgadr(models.Model):
sda_sdgid = models.ForeignKey(SsdgSendung, on_delete=models.CASCADE, blank=True, null=True)
sda_satid = models.CharField(max_length=4, blank=True, null=True)
sda_adrid = models.ForeignKey(SadrAdresse, on_delete=models.CASCADE, blank=True, null=True)
sda_ref = models.CharField(max_length=35, blank=True, null=True)
sda_termbis = models.DateField(blank=True, null=True)
sda_termvon = models.DateField(blank=True, null=True)
class Meta:
db_table = 'ssda_sdgadr'
unique_together = (('sda_sdgid', 'sda_satid'),)
#property
def is_adr_su(self):
return SsdaSdgadr.objects.filter(sda_sdgid = self.sda_sdgid, sda_satid = "SU")
#property
def is_adr_cn(self):
return SsdaSdgadr.objects.filter(sda_sdgid = self.sda_sdgid, sda_satid = "CN")
views.py
Sendungen = SsdaSdgadr.objects.filter(Q(sda_satid__in=["IV"])).order_by('-sda_sdgid__sdg_datum')
...
response = render(request, 'cust/home.html', {
'Sendungen': Sendungen,
})
return response
Template code home.html
{% for la_item in Sendungen %}
<tr>
<td>{{ la_item.sda_sdgid.sdg_sdgid }}</td>
<td>{{ la_item.sda_ref }}</td> <!-- IV.sda_ref OKAY -->
{% for adr in la_item.is_adr_su %}
<td>{{ adr.sda_adrid.adr_adrid }}</td> <!-- SU.sda_adrid OKAY -->
<td>{{ adr.sda_termvon|date }}</td> <!-- SU.sda_termvon OKAY -->
{% endfor %}
{% for adr in la_item.is_adr_cn %}
<td>{{ adr.sda_adrid.adr_adrid }}</td> <!-- CN.sda_adrid OKAY -->
<td>{{ adr.sda_termbis|date }}</td> <!-- CN.sda_termbis OKAY -->
{% endfor %}
</tr>
{% endfor %}