Yes yes yes -- more documentation improvements

git-svn-id: http://code.djangoproject.com/svn/django/trunk@67 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Jacob Kaplan-Moss 2005-07-15 20:37:03 +00:00
parent 05c5dabb8f
commit 604cd7fe14
3 changed files with 223 additions and 27 deletions

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@ -305,4 +305,44 @@ objects fields, then call the object's ``save()`` method::
Creating new objects
====================
...
Creating new objects (i.e. ``INSERT``) is done by creating new instances
of objects then calling save() on them::
>>> p = polls.Poll(id=None,
... slug="eggs",
... question="How do you like your eggs?",
... pub_date=datetime.datetime.now(),
... expire_date=some_future_date)
>>> p.save()
Calling ``save()`` on an object with an id if ``None`` signifies to
Django that the object is new and should be inserted.
Related objects (i.e. ``Choices``) are created using convience functions::
>>> p.add_choice(choice="Over easy", votes=0)
>>> p.add_choice(choice="Scrambled", votes=0)
>>> p.add_choice(choice="Fertilized", votes=0)
>>> p.add_choice(choice="Poached", votes=0)
>>> p.get_choice_count()
4
Each of those ``add_choice`` methods is equivilent to (except obviously much
simpler than)::
>>> c = polls.Choice(id=None,
... poll_id=p.id,
... choice="Over easy",
... votes=0)
>>> c.save()
Note that when using the `add_foo()`` methods, you do not give any value
for the ``id`` field, nor do you give a value for the field that stores
the relation (``poll_id`` in this case).
Deleting objects
================
Just cause we're crazy like that, the delete method is named ``delete()``.
Yeah, you never know what we're going to do next.

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@ -66,12 +66,12 @@ Lawrence, Kansas, USA.
`chicagocrime.org`_.
`Simon Willison`_
Simon is a well-respected Web developer from England. He had a one-year stint
at World Online, during which time he and Adrian developed Django from scratch.
He's enthusiastic, he's passionate about best practices in Web development, and
he really likes squirrels. Probably to a fault. He went back to England to
finish his degree and is poised to continue doing big, exciting things on the Web.
Read his weblog at `simon.incutio.com`_.
Simon is a well-respected Web developer from England. He had a one-year
stint at World Online, during which time he and Adrian developed Django from
scratch. He's enthusiastic, he's passionate about best practices in Web
development, and he really likes squirrels. Probably to a fault. He went
back to England to finish his degree and is poised to continue doing big,
exciting things on the Web. Read his weblog at `simon.incutio.com`_.
`Jacob Kaplan-Moss`_
Jacob is a whipper-snapper from California who spends equal time coding and
@ -102,17 +102,35 @@ How do I get started?
We're working on this documentation as you read this.
What are Django's prerequisites?
--------------------------------
Django requires Python_ 2.3 or later, Apache2_, and mod_python_. You'll
also need a database engine; PostgreSQL_ is recommended, and MySQL_ is
supported.
We're currently working on expanding those options: WSGI_ support is in the
works (which will allow Django to run under CGI, FCGI, etc.), as is support for
a number of other database backends.
.. _Python: http://www.python.org/
.. _Apache2: http://httpd.apache.org/
.. _mod_python: http://www.modpython.org/
.. _PostgreSQL: http://www.postgresql.org/
.. _MySQL: http://www.mysql.com/
.. _WSGI: http://www.python.org/peps/pep-0333.html
The admin interface
===================
The dynamically-generated admin site is ugly! How can I change it?
------------------------------------------------------------------
We think it's very purty, but if you don't agree, you can modify the admin site's
presentation by editing the CSS stylesheet and/or associated image files. The
site is built using semantic HTML, so any changes you'd like to make should be
possible by editing the CSS stylesheet. We've got a `guide to the CSS used
in the admin`_ to get you started.
We think it's very purty, but if you don't agree, you can modify the admin
site's presentation by editing the CSS stylesheet and/or associated image files.
The site is built using semantic HTML, so any changes you'd like to make should
be possible by editing the CSS stylesheet. We've got a `guide to the CSS used in
the admin`_ to get you started.
.. _`guide to the CSS used in the admin`: http://www.djangoproject.com/documentation/admin_css/

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@ -180,8 +180,6 @@ options that are common to all field types. These options are:
``null`` If ``True`` empty values in the field will be
stored as ``NULL`` in the database.
XXX does null imply blank? XXX
``primary_key`` If ``True`` this field is the primary key for the
table. You only need to use this if you don't want
@ -302,8 +300,8 @@ Field Types
meta.ForeignKey(Pizza)
``ForeignKey`` fields take a large number of options for defining how the
relationship should work:
``ForeignKey`` fields take a large number of extra options for defining how
the relationship should work:
======================= ============================================================
Option Description
@ -364,7 +362,7 @@ Field Types
Not used with ``edit_inline``.
``rel_name`` The name of the relation. In the above exmaple,
``rel_name`` The name of the relation. In the above example,
this would default to 'pizza' (so that the
``Toppings`` object would have a ``get_pizza()``
function; if you set ``rel_name`` to "pie", then
@ -431,12 +429,60 @@ Field Types
An IP address, in string format (i.e. "24.124.1.30").
``ManyToManyField``
XXX document once Adrian reworks this XXX
A many-to-many relation to another object. For example (taken from the
``core.flatfiles`` object::
class FlatFile(meta.Model):
fields = (
...
meta.ManyToManyField(Site),
)
Many-to-many relations are a bit different from other fields. First, they
aren't actually a field per se since they use a intermediary join table.
Second, they don't take any of the same options as the rest of the fields,
the only options taken are:
======================= ============================================================
Option Description
======================= ============================================================
``related_name`` See the description of ``related_name`` in
``ManyToOneField``, above.
``filter_interface`` Use a nifty unobtrusive Javascript "filter" interface
instead of the usability-challenged ``<select multiple>``.
The value should be ``meta.HORIZONTAL`` or ``meta.VERTICAL``
(i.e. should the interface be stacked horizontally or
vertically).
``limit_choices_to`` See the description under ``ManyToOneField``, above.
======================= ============================================================
``NullBooleanField``
Like a ``BooleanField``, but allows ``NULL`` as one of the options. Use this
instead of a ``BooleanField`` with ``null=True`` .
``OneToOneField``
Signifies a one-to-one relationship. This is most useful on the primary key
of an object when that object "extends" another object in some way.
For example, if you are building a database of "places", you would build pretty
standard stuff like address, phone number, etc. in the database. If you then
wanted to build a database of restaurants on top of the places, instead of
repeating yourself and replicating those fields in the restaurants object, you
could make ``Restaurant`` have a ``OneToOneField`` to ``Place`` (since
a restaurant "is-a" place). This ``OneToOneField`` will actually replace
the primary key ``id`` field (since one-to-one relations share the same
primary key), and has a few in the admin interface:
* No selection interface is displayed on ``Restaurant`` pages; there will
be one (and only one) ``Restaurant`` for each place.
* On the ``Restaurant`` change list, every single ``Place`` -- weather it
has an associated ``Restaurant`` or not -- will be displayed. Adding
a ``Restaurant`` to a ``Place`` just means filling out the required
``Restaurant`` fields.
``PhoneNumberField``
Validates that the value is a valid phone number.
@ -573,21 +619,113 @@ object, which has the following options (of which only ``fields`` is required):
(This example also has ``search_fields`` defined; see below).
``ordering``
An ordering tuple (see the `Options for models`_, above) that gives a
different ordering for the admin change list. If not given, the
model's default ordering will be used.
An ordering tuple (see the `Options for models`_, above) that gives a
different ordering for the admin change list. If not given, the model's
default ordering will be used.
``save_as``
Enables a "save as" feature on object pages. Normally, objects have
three save options: "Save", "Save and continue editing", and "Save
and add another". If ``save_as`` is ``True``, "Save and add another"
will be replaced by a "Save as" button.
Enables a "save as" feature on object pages. Normally, objects have three
save options: "Save", "Save and continue editing", and "Save and add
another". If ``save_as`` is ``True``, "Save and add another" will be
replaced by a "Save as" button.
``save_on_top``
If this option is ``True``, object pages will have the save buttons
across the top as well as at the bottom of the page.
If this option is ``True``, object pages will have the save buttons across
the top as well as at the bottom of the page.
``search_fields``
A list of fields to provide a text search for. These fields should,
obviously, be some kind of text field.
Model methods
=============
There are a number of methods you can define on model objects to control the
object's behavior. First, any methods you define will be available as methods
of object instances. For example::
class Pizza(meta.Model):
fields = (
...
)
def is_disgusting(self):
return "anchovices" in [topping.name for topping in self.get_topping_list()]
Now, every ``Pizza`` object will have a ``is_disgusting()`` method.
There are a few object methods that have special meaning:
``__repr__``
Django uses ``repr(obj)`` in a number of places, the most notable as the
value inserted into a template when it displays an object. Thus, you should
return a nice, human-readable string for the object's ``__repr__``.
``get_absolute_url``
If an object defines a ``get_absolute_url`` method, it is used to
associate a URL with an object. For example:
def get_absolute_url(self):
return "/pizzas/%i/" % self.id
The most useful place this is used is in the admin interface; if an object
defines ``get_absolute_url`` then the object detail page will have a "View
on site" link that will jump you directly to the object's public view.
``_pre_save``
This method will be called just before the object is saved into the
database; you can use it to (for example) calculate aggregate values from
other fields before the object is saved.
``_post_save``
Called just after the object is saved to the database. This could be used
to update other tables, update cached information, etc.
Module-level methods
--------------------
Since each data class in effect turns into a module, there are times you'll want
to write methods that live in that module. Any model method that begins with
"_module_" is turned into a module-level method::
class Pizza(meta.Model):
fields = (
...
)
def _module_get_pizzas_to_deliver():
return get_list(delivered__exact=False)
This will make the top-level ``pizzas`` module have a ``get_pizzas_to_deliver()``
method::
>>> from django.models.pizza_hut import pizzas
>>> pizzas.get_pizzas_to_deliver()
[ ... ]
Note that the scope of these methods is modified to be the same has the module
scope (so that's how the raw ``get_list`` works).
Manipulator methods
-------------------
Similarly, you can add methods to the object's manipulators (see the formfields
documentation for more on manipulators) by defining methods that being with
"_manipulator_". This is most useful for providing custom validators for certain
fields since manipulators automatically call any method that begins with
"validate"::
class Pizza(meta.Model):
fields = (
...
)
def _manipulator_validate_customer_id(self, field_data, all_data):
from django.core import validators
from django.conf.settings import BAD_CUSTOMER_IDS
if int(field_data) in BAD_CUSTOMER_IDS:
raise validators.ValidationError("We don't deliver to this customer")