النماذج والمخطط وتاريخ الترحيل

from django.conf import settings
settings.configure(
    SECRET_KEY="synthetic-course-key",
    USE_I18N=False, USE_TZ=True,
    INSTALLED_APPS=[],
    DATABASES={"default": {"ENGINE": "django.db.backends.sqlite3", "NAME": ":memory:"}},
    DEFAULT_AUTO_FIELD="django.db.models.AutoField",
    ALLOWED_HOSTS=["testserver"],
)
import django
django.setup()

from django.db import connection, models

class Course(models.Model):
    title = models.CharField(max_length=100)
    seats = models.PositiveIntegerField(default=0)
    class Meta:
        app_label = "lab"

with connection.schema_editor() as editor:
    editor.create_model(Course)
Course.objects.create(title="Django", seats=4)
Course.objects.create(title="Python", seats=2)
print(list(Course.objects.order_by("title").values_list("title", flat=True)))

['Django', 'Python']

القاعدة الوحيدة SQLite الذاكرية والتهيئة المباشرة للعينة لا لإنتاج.

from django.db import migrations, models

class Migration(migrations.Migration):
    dependencies = [("catalog", "0001_initial")]
    operations = [
        migrations.AddField(
            model_name="course", name="seats",
            field=models.PositiveIntegerField(default=0),
        ),
    ]

If reviewed and applied in the declared app: a seats field is added with the stated default.

يفترض المقطع غياب seats سابقا والصفر افتراض تعليمي يحتاج مراجعة بيانات حقيقية، ولا يطبق.