[web2py] Tag handling suggestions

2011-10-10 Thread pbreit 
Anyone have a quick perspective on the pros/cons of handling tags like 
this:

Option 1:
db.define_table('item',Field('tags','list:string'))

Option 2:
db.define_table('tag')
db.define_table('item',Field('tags','list:reference tag'))

Options 3:
db.define_table('item')
db.define_table('tag')
db.define_table('item_tag',Field('item'),Field('tag'))

Re: [web2py] Tag handling suggestions

2011-10-10 Thread Bruno Rocha 
On Mon, Oct 10, 2011 at 9:36 PM, pbreit pbreitenb...@gmail.com wrote:

 Option 1:
 db.define_table('item',Field('tags','list:string'))



I am using the Option 1.

for me it is better because I end with pure Python list, which I can run
map, reduce, filter etc...

also contains and belongs are very helpful and fast.

I also think it is the less complicated way.

--
Bruno Rocha
[ About me: http://zerp.ly/rochacbruno ]
[ Aprenda a programar: http://CursoDePython.com.br  ]

Re: [web2py] Tag handling suggestions

2011-10-10 Thread Bruno Rocha 
Clarifying:

Option 1:
 db.define_table('item',Field('tags','list:string'))


*Pro*:
Easy search:
tag = request.args(0)
results = db(db.item.tags.contains(tag)).select()

*Con*:
build a tag cloud
records = db(db.item.id0).select(db.item.tags)
alltags = [] # loop thought records to populate the tags list (here you can
use reduce, list comprehension)



 Option 2:
 db.define_table('tag')
 db.define_table('item',Field('tags','list:reference tag'))


*Pro*:
build a tag clous
alltags = [ r.tag for r in db(db.tag.id0).select('tag')]

*Con:*
Search is expensive
tag = request.args(0) # it is a string like: book
tag_id = db.tag(tag=tag)[0].id # or a taglist
records = db(db.item.tag.contains(tag_id)).select()


Options 3:
 db.define_table('item')
 db.define_table('tag')
 db.define_table('item_tag',Field('item'),Field('tag'))


*Con:*
In this case I see Tag searching and tagcloud as a expensive process.

But, certainly Massimo has a DAL trick to solve this use case in one line of
code ;)

--
Bruno Rocha
[ About me: http://zerp.ly/rochacbruno ]
[ Aprenda a programar: http://CursoDePython.com.br ]