On Oct 28, 3:12 pm, Scott LaBounty <[email protected]> wrote:
> OK, I looked at the nested sets and they look complex and I looked at the
> "with recursive" and it doesn't look like sqlite (which I use for just
> hacking around) doesn't support it. So ... any other ideas or do I just need
> to suck it up and learn nested sets or suck it up and use a better database.
Nested sets are significantly more complex than trees, and I don't
know of a Sequel plugin that handles them. SQLite doesn't support
common table expressions.
It's not that using trees in SQLite is going to cause problems, it's
just more work to get all descendants. If you look at the Advanced
Associations page on the website, it shows how to handle such a case.
One simpler way to handle this is a text field that stores the path.
Assuming it's indexed and that prefixed searching uses the index, this
should be a fairly fast approach:
1
|
-------
| |
2 3
|
-------
| |
4 5
Paths would be:
1 - '1'
2 - '1/2'
3 - '1/3'
4 - '1/3/4'
5 - '1/3/5'
Then if you want all descendants/ancestors of 3:
node = Tree[3]
descendents = Tree.filter(:path.like("#{node.path}/%")).order
(:path).all
ancestors = Tree.filter(:id=>node.path.split('/').map{|x|
x.to_i}).order(:path.desc).all
I haven't tried that, and there are probably issues with the approach,
but it may work for simple cases.
Jeremy
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"sequel-talk" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/sequel-talk?hl=en
-~----------~----~----~----~------~----~------~--~---
