I've made a mistake in my tip, please replace:
db.comment._common_filter = inherit_common_filter(db, db.comment)
with:
db.comment._common_filter = inherit_common_filter(db,
db.comment.post)
Sorry for this one.
On Jan 29, 10:46 am, guruyaya <guruy...@gmail.com> wrote:
> I wrote this function, to help out with a project I'm working on, that
> has an extensive use of the common filter functionality (describes in
> chapter 6 of the web2py book).
> Say you have a blog, containing active, and inactive posts:
>
> db.define_table('post',
> Field('subject'),
> Field('post','text'),
> Field('is_active','boolean'),
> common_filter = lambda query: db.post.is_active == True
> )
>
> And we have comments on posts:
> db.define_table('comment',
> Field('post',db.post),
> Field('comment','text')
> )
>
> Running db(db.comment.id > 0).select(), will select all comments,
> including those posts where is_active is False.
>
> Solution:
> use this function in a model, module, whatever:
>
> def inherit_common_filter(db, col):
> ''' gets the common filter of a field refrenced
> '''
> ref_table_name = col.type.replace('reference ', '')
> ref_table = db[ref_table_name]
> ref_table_filter = ref_table._common_filter
>
> return lambda query:
> col.belongs(db(ref_table_filter(query))._select(ref_table.id))
>
> Now, the new model looks like:
> db.define_table('comment',
> Field('post',db.post),
> Field('comment','text')
> )
> db.comment._common_filter = inherit_common_filter(db, db.comment)
>
> Now Running db(db.comment.id > 0).select(), will select all comments
> that are set to is_active == True.
>
> Hope you'll find this useful
