django最佳实践之数据迁移执行migrate后自动初始化数据

django数据迁移执行migrate后自动插入初始化数据之官方版本

本文档参考django.contrib.sites中相关实践

1.直接上结论

设置sql执行方法->利用信号post_migrate自动执行

2.具体实现

完整代码请自行查看django.contrib.sites相关代码

2.1 django.contrib.sites.management 中实现sql生成和执行方法create_default_site

"""
Creates the default Site object.
"""

from django.apps import apps as global_apps
from django.conf import settings
from django.core.management.color import no_style
from django.db import DEFAULT_DB_ALIAS, connections, router


def create_default_site(app_config, verbosity=2, interactive=True, using=DEFAULT_DB_ALIAS, apps=global_apps, **kwargs):
    try:
        Site = apps.get_model('sites', 'Site')
    except LookupError:
        return

    if not router.allow_migrate_model(using, Site):
        return

    if not Site.objects.using(using).exists():
        # The default settings set SITE_ID = 1, and some tests in Django's test
        # suite rely on this value. However, if database sequences are reused
        # (e.g. in the test suite after flush/syncdb), it isn't guaranteed that
        # the next id will be 1, so we coerce it. See #15573 and #16353. This
        # can also crop up outside of tests - see #15346.
        if verbosity >= 2:
            print("Creating example.com Site object")
        Site(pk=getattr(settings, 'SITE_ID', 1), domain="example.com", name="example.com").save(using=using)

        # We set an explicit pk instead of relying on auto-incrementation,
        # so we need to reset the database sequence. See #17415.
        sequence_sql = connections[using].ops.sequence_reset_sql(no_style(), [Site])
        if sequence_sql:
            if verbosity >= 2:
                print("Resetting sequence")
            with connections[using].cursor() as cursor:
                for command in sequence_sql:
                    cursor.execute(command)

2.2 django.contrib.sites.apps 使用post_migrate信号

from django.apps import AppConfig
from django.db.models.signals import post_migrate
from django.utils.translation import gettext_lazy as _

from .management import create_default_site


class SitesConfig(AppConfig):
    name = 'django.contrib.sites'
    verbose_name = _("Sites")

    def ready(self):
        post_migrate.connect(create_default_site, sender=self)