About Checking if a CharField is Not Empty

Here's how you can check if a CharField is not empty in a Queryset:

from django.db import models
from django.db.models.functions import Length
from pictures.models import Picture

models.CharField.register_lookup(Length, "length")

qs = Picture.objects.annotate(
    alt_text_exists=models.Case(
        models.When(
            alt_text__length__gt=0,
            then=models.Value(True)
        ),
        default=models.Value(False),
        output_field=models.BooleanField(),
    )
)
# Get pictures with missing Alt Text
qs = qs.filter(alt_text_exists=False)