mezzanine的page表

class Orderable(with_metaclass(OrderableBase, models.Model)):
    """
    Abstract model that provides a custom ordering integer field
    similar to using Meta's ``order_with_respect_to``, since to
    date (Django 1.2) this doesn't work with ``ForeignKey("self")``,
    or with Generic Relations. We may also want this feature for
    models that aren't ordered with respect to a particular field.
    """

    _order = OrderField(_("Order"), null=True)

    class Meta:
        abstract = True
class OrderableBase(ModelBase):
    """
    Checks for ``order_with_respect_to`` on the model's inner ``Meta``
    class and if found, copies it to a custom attribute and deletes it
    since it will cause errors when used with ``ForeignKey("self")``.
    Also creates the ``ordering`` attribute on the ``Meta`` class if
    not yet provided.
    """
class Displayable(Slugged, MetaData, TimeStamped):
    """
    Abstract model that provides features of a visible page on the
    website such as publishing fields. Basis of Mezzanine pages,
    blog posts, and Cartridge products.
    """

    status = models.IntegerField(_("Status"),
        choices=CONTENT_STATUS_CHOICES, default=CONTENT_STATUS_PUBLISHED,
        help_text=_("With Draft chosen, will only be shown for admin users "
            "on the site."))
    publish_date = models.DateTimeField(_("Published from"),
        help_text=_("With Published chosen, won't be shown until this time"),
        blank=True, null=True, db_index=True)
    expiry_date = models.DateTimeField(_("Expires on"),
        help_text=_("With Published chosen, won't be shown after this time"),
        blank=True, null=True)
    short_url = models.URLField(blank=True, null=True)
    in_sitemap = models.BooleanField(_("Show in sitemap"), default=True)

    objects = DisplayableManager()
    search_fields = {"keywords": 10, "title": 5}

    class Meta:
        abstract = True
class Slugged(SiteRelated):
    """
    Abstract model that handles auto-generating slugs. Each slugged
    object is also affiliated with a specific site object.
    """

    title = models.CharField(_("Title"), max_length=500)
    slug = models.CharField(_("URL"), max_length=2000, blank=True, null=True,
            help_text=_("Leave blank to have the URL auto-generated from "
                        "the title."))

    class Meta:
        abstract = True

class SiteRelated(models.Model):
    """
    Abstract model for all things site-related. Adds a foreignkey to
    Django's ``Site`` model, and filters by site with all querysets.
    See ``mezzanine.utils.sites.current_site_id`` for implementation
    details.
    """

    objects = CurrentSiteManager()

    class Meta:
        abstract = True

    site = models.ForeignKey("sites.Site", editable=False)

class MetaData(models.Model):
    """
    Abstract model that provides meta data for content.
    """

    _meta_title = models.CharField(_("Title"), null=True, blank=True,
        max_length=500,
        help_text=_("Optional title to be used in the HTML title tag. "
                    "If left blank, the main title field will be used."))
    description = models.TextField(_("Description"), blank=True)
    gen_description = models.BooleanField(_("Generate description"),
        help_text=_("If checked, the description will be automatically "
                    "generated from content. Uncheck if you want to manually "
                    "set a custom description."), default=True)
    keywords = KeywordsField(verbose_name=_("Keywords"))
class TimeStamped(models.Model):
    """
    Provides created and updated timestamps on models.
    """

    class Meta:
        abstract = True

    created = models.DateTimeField(null=True, editable=False)
    updated = models.DateTimeField(null=True, editable=False)

lass Page(BasePage):
    """
    A page in the page tree. This is the base class that custom content types
    need to subclass.
    """

    parent = models.ForeignKey("Page", blank=True, null=True,
        related_name="children")
    in_menus = MenusField(_("Show in menus"), blank=True, null=True)
    titles = models.CharField(editable=False, max_length=1000, null=True)
    content_model = models.CharField(editable=False, max_length=50, null=True)
    login_required = models.BooleanField(_("Login required"), default=False,
        help_text=_("If checked, only logged in users can view this page"))

    class Meta:
        verbose_name = _("Page")
        verbose_name_plural = _("Pages")
        ordering = ("titles",)
        order_with_respect_to = "parent"

model的Meta abstract为True的，不会生成数据库表。

CREATE TABLE "pages_page" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "keywords_string" varchar(500) NOT NULL, "title" varchar(500) NOT NULL, "slug" varchar(2000) NULL, "_meta_title" varchar(500) NULL, "description" text NOT NULL, "gen_description" bool NOT NULL, "created" datetime NULL, "updated" datetime NULL, "status" integer NOT NULL, "expiry_date" datetime NULL, "short_url" varchar(200) NULL, "in_sitemap" bool NOT NULL, "_order" integer NULL, "in_menus" varchar(100) NULL, "titles" varchar(1000) NULL, "content_model" varchar(50) NULL, "login_required" bool NOT NULL, "parent_id" integer NULL REFERENCES "pages_page" ("id"), "site_id" integer NOT NULL REFERENCES "django_site" ("id"), "publish_date" datetime NULL);

CREATE INDEX "pages_page_9365d6e7" ON "pages_page" ("site_id");

CREATE INDEX "pages_page_6be37982" ON "pages_page" ("parent_id");

CREATE INDEX "pages_page_76776489" ON "pages_page" ("publish_date");