diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/topics/db/queries.txt | 2 | ||||
| -rw-r--r-- | docs/topics/templates.txt | 39 |
2 files changed, 41 insertions, 0 deletions
diff --git a/docs/topics/db/queries.txt b/docs/topics/db/queries.txt index 5c4941fbf2..b0d053c2e9 100644 --- a/docs/topics/db/queries.txt +++ b/docs/topics/db/queries.txt @@ -823,6 +823,8 @@ a join with an ``F()`` object, a ``FieldError`` will be raised:: # THIS WILL RAISE A FieldError >>> Entry.objects.update(headline=F('blog__name')) +.. _topics-db-queries-related: + Related objects =============== diff --git a/docs/topics/templates.txt b/docs/topics/templates.txt index 5586ed8c12..492d23d716 100644 --- a/docs/topics/templates.txt +++ b/docs/topics/templates.txt @@ -569,6 +569,45 @@ This doesn't affect what happens to data coming from the variable itself. The variable's contents are still automatically escaped, if necessary, because they're beyond the control of the template author. +.. _template-accessing-methods: + +Accessing method calls +====================== + +Most method calls attached to objects are also available from within templates. +This means that templates have access to much more than just class attributes +(like field names) and variables passed in from views. For example, the Django +ORM provides the :ref:`"entry_set"<topics-db-queries-related>` syntax for +finding a collection of objects related on a foreign key. Therefore, given +a model called "comment" with a foreign key relationship to a model called +"task" you can loop through all comments attached to a given task like this:: + + {% for comment in task.comment_set.all %} + {{ comment }} + {% endfor %} + +Similarly, :doc:`QuerySets<ref/models/querysets>` provide a ``count()`` method +to count the number of objects they contain. Therefore, you can obtain a count +of all comments related to the current task with:: + + {{ task.comment_set.all.count }} + +And of course you can easily access methods you've explicitly defined on your +own models:: + + # In model + class Task(models.Model): + def foo(self): + return "bar" + + # In template + {{ task.foo }} + +Because Django intentionally limits the amount of logic processing available +in the template language, it is not possible to pass arguments to method calls +accessed from within templates. Data should be calculated in views, then passed +to templates for display. + .. _template-built-in-reference: Using the built-in reference |