Actually mine was an example. as_trees() does not dictate a model. The only
requirement is that the model must have a self referencing field. You can
call it any way you like it. You can pass its name as first argument of
as_trees().
On Monday, 21 October 2013 05:55:44 UTC-5, Niphlod wrote:
>
> ouch.... the easiest model to update, the worst to query.
> I was going to post a plugin for threaded comments but then life kicked in
> with lots of other requirements, and then other things got priority in
> web2py.
> I don't think this will be compatible with what I've done 'cause I use a
> totally different model, but alas, this is better than no plugin at all.
>
> On Monday, October 21, 2013 5:57:00 AM UTC+2, Massimo Di Pierro wrote:
>>
>> It is a recurrent problem that is displays tree-like structures like
>> threaded comments. For example:
>>
>> db.define_table('post',
>> Field('parent_id','reference post'),
>> Field('body'))
>>
>> where each comment has a body and a parent_id (parent_id==None for the
>> root comment(s))
>> We can populate the comments with some dummy data:
>>
>> def make_up_data():
>> import random, uuid
>> ids = [None]
>> for k in range(100):
>> ids.append(db.post.insert(parent_id=random.choice(ids),
>> body=str(uuid.uuid4())))
>> if k==0:
>> ids.pop(None)
>> if db(db.post).isempty(): make_up_data()
>>
>> The new feature in trunk allows you to select the comments are organized
>> them into trees.
>>
>> roots = db(db.post).select().as_trees()
>>
>> This returns a list of parent nodes. Each not stores its own children,
>> recursively.
>>
>> Now you can print them all using a tree traversal:
>>
>> def show(row,n=0):
>> return ' '*n+row.body+'\n'+''.join(show(c,n+1) for c in
>> row.children)
>> print show(roots[0])
>>
>> Notice you can specify the name of the parent field:
>>
>> roots = db(db.post).select().as_trees(parent_name="parent_id")
>>
>> Please let me know if you think this can be improved.
>>
>>
--
Resources:
- http://web2py.com
- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
- https://code.google.com/p/web2py/issues/list (Report Issues)
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