Table (relation) cannot be found on Postgres

alexandremjacques · March 29, 2025, 10:19am

Hi.

I have a legacy Postgres database that I don’t have any control over. I’m trying to create a Django app that, in a separate database connection, also connects to the legacy one. To do that, I created a Database Router that has a default connection (for Django models and control tables) and a legacy that points to the database in question:

DATABASES = {
    'default': env.db('DEFAULT_DATABASE_URL'),
    'legacy': env.db('LEGACY_DATABASE_URL'),
}

DATABASE_ROUTERS = ["apps.core.routers.DefaultRouter", "apps.core.routers.LegacyRouter"]

I can see that the connections are ok (I see no errors on server start and if, I change the URLs to something invalid, I do see connection errors);
Using the Django Toolbar I can check the generated query and that the connection being used by the engine is, in fact, the legacy one:

If I copy that query and run it against the database it works but if I try to load a model (PaintColor) that maps to the same database table, I receive a relation "PaintColor" does not exist error.

One thing to notice is that the legacy database has a quoteReturningIdentifiers set to true and that affects how I write queries in any database client: I have to quote almost every identifier (table and column names). But, as I mentioned, if I take the Django generated query from DT, I see no issues.

Any help is appreciated.

TIA

KenWhitesell · March 29, 2025, 11:50am

It’s difficult-to-impossible to diagnose errors from a description.

Please post the actual code being used here that is throwing the error.

alexandremjacques · March 29, 2025, 1:39pm

Sure!

Since it’s a new project where I was trying to prove this concept of 2 different DBs, I have a simple structure:

Just one app called apps.acotone
Two routers
One simple view, one model (PaintColor)

settings.py

DATABASES = {
    'default': env.db('DEFAULT_DATABASE_URL'),
    'legacy': env.db('LEGACY_DATABASE_URL'),
}

DATABASE_ROUTERS = ["apps.acotone.routers.DefaultRouter", "apps.acotone.routers.LegacyRouter"]

routers.py

class DefaultRouter:
    route_app_labels = {"auth", "contenttypes"}

    def db_for_read(self, model, **hints):
        if model._meta.app_label in self.route_app_labels:
            return "default"
        return None

    def db_for_write(self, model, **hints):
        if model._meta.app_label in self.route_app_labels:
            return "default"
        return None

    def allow_relation(self, obj1, obj2, **hints):
        if (
                obj1._meta.app_label in self.route_app_labels
                or obj2._meta.app_label in self.route_app_labels
        ):
            return True
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        if app_label in self.route_app_labels:
            return db == "default"
        return None


class LegacyRouter:
    route_app_labels = {"acotone"}

    def db_for_read(self, model, **hints):
        if model._meta.app_label in self.route_app_labels:
            return "legacy"
        return None

    def db_for_write(self, model, **hints):
        if model._meta.app_label in self.route_app_labels:
            return "legacy"
        return None

    def allow_relation(self, obj1, obj2, **hints):
        if (
                obj1._meta.app_label in self.route_app_labels
                or obj2._meta.app_label in self.route_app_labels
        ):
            return True
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        if app_label in self.route_app_labels:
            return db == "legacy"
        return None

views.py

from django.shortcuts import render
from django.views import View

from apps.acotone.models import PaintColor


class PaintColorsHome(View):
    def get(self, request):
        paint_colors = PaintColor.objects.all()

        context = {
            'paint_colors': paint_colors,
        }

        return render(request, 'acotone_home.html', context)

models.py

from django.db import models


class PaintColor(models.Model):
    color_name = models.CharField(max_length=255, db_column='colorName', primary_key=True)
    color_notation = models.CharField(max_length=255, db_column='colorNotation')
    color_type = models.CharField(max_length=255, db_column='colorType')
    red_value = models.IntegerField(db_column='redValue')
    green_value = models.IntegerField(db_column='greenValue')
    blue_value = models.IntegerField(db_column='blueValue')
    color_family = models.CharField(max_length=255, db_column='colorFamily')
    color_order = models.IntegerField(db_column='colorOrder')
    status = models.CharField(max_length=255, db_column='status')

    class Meta:
        db_table = "PaintColor"
        managed = False

The database (sorry, I can’t disclosure much more):

The error message:

Thanks again

KenWhitesell · March 29, 2025, 2:20pm

We need to see the complete error message with the traceback from the server console, not the summary provided on the error page.

KenWhitesell · March 29, 2025, 2:23pm

Are you sure that this is the app label being passed to the router?

I would suggest adding a print statement in your db_for_read method to see what’s being supplied.

alexandremjacques · March 29, 2025, 4:45pm

Yeah. I’m sure. I did print that to make sure. I’m including the traceback with some debugging statements for db_for_read().

From DT I can see that it tries 21 times before failing (hence the repeated logging - I removed some since it’d be redundant).

...
[DEBUG] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,025 - apps.acotone.routers:db_for_read:40 - LegacyRouter model._meta.app_label: acotone
[DEBUG] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,031 - apps.acotone.routers:db_for_read:37 - LegacyRouter.db_for_read model: <class 'apps.acotone.models.PaintColor'>
[DEBUG] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,031 - apps.acotone.routers:db_for_read:40 - LegacyRouter model._meta.app_label: acotone
[DEBUG] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,039 - apps.acotone.routers:db_for_read:37 - LegacyRouter.db_for_read model: <class 'apps.acotone.models.PaintColor'>
[DEBUG] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,039 - apps.acotone.routers:db_for_read:40 - LegacyRouter model._meta.app_label: acotone
[DEBUG] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,046 - apps.acotone.routers:db_for_read:37 - LegacyRouter.db_for_read model: <class 'apps.acotone.models.PaintColor'>
[DEBUG] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,046 - apps.acotone.routers:db_for_read:40 - LegacyRouter model._meta.app_label: acotone
[ERROR] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,069 - django.request:log_response:248 - Internal Server Error: /acotone/
Traceback (most recent call last):
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/psycopg/cursor.py", line 97, in execute
    raise ex.with_traceback(None)
psycopg.errors.UndefinedTable: relation "PaintColor" does not exist
LINE 1: ...ntColor"."colorOrder", "PaintColor"."status" FROM "PaintColo...
                                                             ^

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/views/generic/base.py", line 104, in view
    return self.dispatch(request, *args, **kwargs)
           ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/views/generic/base.py", line 143, in dispatch
    return handler(request, *args, **kwargs)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/apps/acotone/views.py", line 15, in get
    return render(request, 'acotone_home.html', context)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/shortcuts.py", line 25, in render
    content = loader.render_to_string(template_name, context, request, using=using)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/loader.py", line 62, in render_to_string
    return template.render(context, request)
           ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/backends/django.py", line 107, in render
    return self.template.render(context)
           ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/base.py", line 171, in render
    return self._render(context)
           ~~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/test/utils.py", line 114, in instrumented_test_render
    return self.nodelist.render(context)
           ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/base.py", line 1008, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
                               ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/base.py", line 969, in render_annotated
    return self.render(context)
           ~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/loader_tags.py", line 159, in render
    return compiled_parent._render(context)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/test/utils.py", line 114, in instrumented_test_render
    return self.nodelist.render(context)
           ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/base.py", line 1008, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
                               ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/base.py", line 969, in render_annotated
    return self.render(context)
           ~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/loader_tags.py", line 65, in render
    result = block.nodelist.render(context)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/base.py", line 1008, in render
    return SafeString("".join([node.render_annotated(context) for node in self]))
                               ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/base.py", line 969, in render_annotated
    return self.render(context)
           ~~~~~~~~~~~^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/template/defaulttags.py", line 199, in render
    len_values = len(values)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 382, in __len__
    self._fetch_all()
    ~~~~~~~~~~~~~~~^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 1928, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
                         ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 91, in __iter__
    results = compiler.execute_sql(
        chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size
    )
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/sql/compiler.py", line 1574, in execute_sql
    cursor.execute(sql, params)
    ~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/debug_toolbar/panels/sql/tracking.py", line 235, in execute
    return self._record(super().execute, sql, params)
           ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/debug_toolbar/panels/sql/tracking.py", line 160, in _record
    return method(sql, params)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 122, in execute
    return super().execute(sql, params)
           ~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 79, in execute
    return self._execute_with_wrappers(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        sql, params, many=False, executor=self._execute
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 92, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 100, in _execute
    with self.db.wrap_database_errors:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/utils.py", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/psycopg/cursor.py", line 97, in execute
    raise ex.with_traceback(None)
django.db.utils.ProgrammingError: relation "PaintColor" does not exist
LINE 1: ...ntColor"."colorOrder", "PaintColor"."status" FROM "PaintColo...
                                                             ^
[ERROR] [7ddf800f97314c0ba60ebb5f9ba4d4b4] 2025-03-29 17:26:46,110 - django.server:log_message:213 - "GET /acotone/ HTTP/1.1" 500 249489

KenWhitesell · March 29, 2025, 7:13pm

When you test this manually, are you using the same credentials as what your Django code is using?

What happens if you use the manage.py dbshell command to open up the database connection? Does that work?

What if you open the regular Django shell and try to run the query? (PaintColor.objects.all())

If that doesn’t work, what happens then if you then run that query with the using clause?

alexandremjacques · March 29, 2025, 8:20pm

When you test this manually, are you using the same credentials as what your Django code is using?

Yes. I have just 1 set of credentials to access the legacy DB.

What happens if you use the manage.py dbshell command to open up the database connection? Does that work?

It does. If I \dI can see Django tables:

(.venv) .venv ❯ ./manage.py dbshell
psql (17.4, server 16.4 (Debian 16.4-1.pgdg120+1))
SSL connection (protocol: TLSv1.3, cipher: TLS_AES_256_GCM_SHA384, compression: off, ALPN: none)
Type "help" for help.

tintometricoadmin=> \d
                            List of relations
 Schema |             Name              |   Type   |        Owner         
--------+-------------------------------+----------+----------------------
 public | auth_group                    | table    | tintometricoadminusr
 public | auth_group_id_seq             | sequence | tintometricoadminusr
 public | auth_group_permissions        | table    | tintometricoadminusr
 public | auth_group_permissions_id_seq | sequence | tintometricoadminusr
 public | auth_permission               | table    | tintometricoadminusr
 public | auth_permission_id_seq        | sequence | tintometricoadminusr
 public | django_admin_log              | table    | tintometricoadminusr
 public | django_admin_log_id_seq       | sequence | tintometricoadminusr
 public | django_content_type           | table    | tintometricoadminusr
 public | django_content_type_id_seq    | sequence | tintometricoadminusr
 public | django_migrations             | table    | tintometricoadminusr
 public | django_migrations_id_seq      | sequence | tintometricoadminusr
 public | django_session                | table    | tintometricoadminusr
 public | user                          | table    | tintometricoadminusr
 public | user_groups                   | table    | tintometricoadminusr
 public | user_groups_id_seq            | sequence | tintometricoadminusr
 public | user_user_permissions         | table    | tintometricoadminusr
 public | user_user_permissions_id_seq  | sequence | tintometricoadminusr
(18 rows)

tintometricoadmin=>

What if you open the regular Django shell and try to run the query? (PaintColor.objects.all())

Same behavior:

(.venv) .venv ❯ ./manage.py shell
Python 3.13.1 (v3.13.1:06714517797, Dec  3 2024, 14:00:22) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from apps.acotone.models import PaintColor
>>> PaintColor.objects.all()
[DEBUG] [none] 2025-03-29 20:14:29,406 - apps.acotone.routers:db_for_read:37 - LegacyRouter.db_for_read model: <class 'apps.acotone.models.PaintColor'>
[DEBUG] [none] 2025-03-29 20:14:29,406 - apps.acotone.routers:db_for_read:40 - LegacyRouter model._meta.app_label: acotone
Traceback (most recent call last):
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/psycopg/cursor.py", line 97, in execute
    raise ex.with_traceback(None)
psycopg.errors.UndefinedTable: relation "PaintColor" does not exist
LINE 1: ...ntColor"."colorOrder", "PaintColor"."status" FROM "PaintColo...
                                                             ^

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 376, in __repr__
    data = list(self[: REPR_OUTPUT_SIZE + 1])
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 400, in __iter__
    self._fetch_all()
    ~~~~~~~~~~~~~~~^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 1928, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
                         ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 91, in __iter__
    results = compiler.execute_sql(
        chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size
    )
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/sql/compiler.py", line 1574, in execute_sql
    cursor.execute(sql, params)
    ~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 122, in execute
    return super().execute(sql, params)
           ~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 79, in execute
    return self._execute_with_wrappers(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        sql, params, many=False, executor=self._execute
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 92, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 100, in _execute
    with self.db.wrap_database_errors:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/utils.py", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/psycopg/cursor.py", line 97, in execute
    raise ex.with_traceback(None)
django.db.utils.ProgrammingError: relation "PaintColor" does not exist
LINE 1: ...ntColor"."colorOrder", "PaintColor"."status" FROM "PaintColo...

If that doesn’t work, what happens then if you then run that query with the using clause?

Also, same issue.

(.venv) .venv ❯ ./manage.py shell
Python 3.13.1 (v3.13.1:06714517797, Dec  3 2024, 14:00:22) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from apps.acotone.models import PaintColor
>>> PaintColor.objects.using('legacy').all()
Traceback (most recent call last):
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/psycopg/cursor.py", line 97, in execute
    raise ex.with_traceback(None)
psycopg.errors.UndefinedTable: relation "PaintColor" does not exist
LINE 1: ...ntColor"."colorOrder", "PaintColor"."status" FROM "PaintColo...
                                                             ^

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 376, in __repr__
    data = list(self[: REPR_OUTPUT_SIZE + 1])
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 400, in __iter__
    self._fetch_all()
    ~~~~~~~~~~~~~~~^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 1928, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
                         ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/query.py", line 91, in __iter__
    results = compiler.execute_sql(
        chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size
    )
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/models/sql/compiler.py", line 1574, in execute_sql
    cursor.execute(sql, params)
    ~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 122, in execute
    return super().execute(sql, params)
           ~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 79, in execute
    return self._execute_with_wrappers(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        sql, params, many=False, executor=self._execute
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 92, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 100, in _execute
    with self.db.wrap_database_errors:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/utils.py", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/alexandremjacques/Development/Projects/Python/tintometrico_admin/.venv/lib/python3.13/site-packages/psycopg/cursor.py", line 97, in execute
    raise ex.with_traceback(None)
django.db.utils.ProgrammingError: relation "PaintColor" does not exist
LINE 1: ...ntColor"."colorOrder", "PaintColor"."status" FROM "PaintColo...
                                                             ^

KenWhitesell · March 29, 2025, 10:40pm

This is showing you your default database. You would need to use the --database parameter to connect to the legacy database.

Also, once you’re connected and can verify that you see a table named “PaintColor”, issue a query to retrieve data from that table. (It doesn’t have to be everything. select * from PaintColor limit 1; would be sufficient. All you’re looking to determine is that Django can see and access that table.)

white-seolpyo · March 31, 2025, 12:48am

i think you do not migrate multiple database.
If you have set up multiple databases, you must perform migration for each database.

# migrate default database
$ python manage.py migrate
# migrate additinal database
$ python manage.py migrate --database={DATABASES key}

alexandremjacques · April 7, 2025, 12:52pm

Hi! I’m very embarassed to say that I found the issue: it was the wrong database URL registered in the LEGACY_DATABASE_URL env variable.

Sorry for taking everyone’s time.

Topic		Replies	Views
Testing when connecting to existing database Mystery Errors	0	476	March 27, 2024
Postgres Relation Does not Exist Using the ORM	15	10292	May 4, 2023
Problems with multiple databases migrations and tests Using Django	6	6376	February 18, 2021
Error migrate table model users Using the ORM	2	872	February 22, 2023
Allow 'Database Router' to override default `connection` ORM	6	226	January 28, 2025

Table (relation) cannot be found on Postgres

Related topics