migrate throws OperationError no such table

Using Django
1

Sometime during the last year I started running into an error when I ran makemigrations and migrate. After some investigation I arrived at the work-around to run these with --skip-checks to essentially ignore the errors since everything seemed to work.

Except tests, I recently learned, since to my knowledge there was no way to add --skip-checks to the django test runner without some custom code. And it started to seem like I was now having to go out of the way to make things work which seemed to indicate some deeper misunderstanding.

So I went back to the views where the errors were getting thrown and it seemed that all were related to the creation of a FilterSet class to use in a TableView. Specifically I was trying to use list comprehensions in place of a queryset. In my defense I don’t recall knowing about a ModelChoiceFilter when I first wrote the code. I was able to address all of the no such table OperationErrors that were thrown during makemigrations or migrate by performing a code change similar to that shown in the screenshot of a diff below:

image
image1906×685 85.6 KB

Could someone explain why this addressed the issue?

2

Please do not post images. Copy and paste your code in a formatted code block.

3

What code changes were made to resolve the migration errors, and how effective were they?

4

Essentially resolving the issue came down to some debugging: For each error where I saw “no such table” I identified the source code and made a change that would explicitly call out a model.

The errors seemed to be entirely addressed by these changes (I made about 3+ changes - all to sub-classes of the FilterSet class.

So for the example shown in the visual diff image attached, I was creating an AssetFilter(FilterSet) class that relied on the Asset model. migrate would complain that the organization table did not exist. I replaced what I thought was a generated list of Organization Ids and Names implemented as a ChoiceFilter with a ModelChoiceFilter set to the queryset of the Organization model manager.

-    organization = ChoiceFilter(
+    organization = ModelChoiceFilter(
         label="Organization",
-        lookup_expr="exact",
-        choices=[(org.id, org.name) for org in Organization.objects.all().filter()],
+        empty_label="All Organizations",
+        queryset=Organization.objects.all(),
         widget=Select({"class": "form-control form-select-sm"}),
-        empty_label="All Organizations",
     )