chris / better_nested_set

Can you provide a code sample, or better, a failing test case? Also, looks like you're using Rails 2.3.4. I'm still on 2.3.3, so it could be an issue that's come up with 2.3.4. I expect to jump to Rails 2.3.5 in the next few weeks, but until then won't know if that's the issue.

The real question is how do I create a root node?

Currently I'm using:
a = Class.new()
a.name = "text"
a.save

This generates the error above...

Ok, now I'm using 2.3.3 and I'm getting the same error:
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract_adapter.rb:212:in log': Mysql::Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1: SELECT max(hosttrees.rgt) AS max_rgt FROMhosttrees` WHERE (parent_id = ) (ActiveRecord::StatementInvalid)

Can you please let me know how I should create a root node for a tree?

Regards

The way you're doing it, or say Class.create(:name => 'text'), should work fine. I just did it and it works fine for me. When I do that, I see the following SELECT:

SELECT max(locations.rgt) AS max_rgt FROM locations WHERE (1 = 1)

So, not sure what's going on with the "parent_id=" bit. Do you have any non-standard configuration or naming? I assume you have parent_id, lft, and rgt columns in your table? It's also a bit unusual looking to see "hosttrees", instead of "host_trees", but maybe your class is named "Hosttree" (instead of "HostTree")?

The problem was with a syntax error in the model file.

Regards

I'm not sure. When you say the structure is corrupt, is it corrupt right after the deletes, as in, have you reloaded the objects you are examining for correctness? I haven't had any problems. I'm using a smaller number of items in our case, but I don't see how the number would matter at all (the code either works or it doesn't). Are any exceptions being thrown?

Hi chris, yes, i reloaded the objects after the deletes.
For example before the script, i had a structure like this:

root
  a
    a1
      a11
      a12
    a2
    a3
  b
    b1
    b2
    b3
  etc..

Then after the creation/destroy i had something like:

root
  a
    a1
      a11
      a12
    a2
    a3
      b
        b1
        b2
        b3
    etc..

Having another group of categories under another child (luckily only for lft and rgt, parent_id wasn't touched so i was able to just run a renumber_full_tree)

The only problem i think about is that i got all the categories and then checked them, like
Category.all.each do |category|
category.destroy if category.something = '...' and category.all_children_count.zero? end

Without reloading all the categories, but i think that this isn't the problems as in the before_destroy of the plugin there is a:

   self.reload # in case a concurrent move has altered the indexes

which should be the solution for this cases

There weren't any exceptions or other outputs (just that for the destroy it took a while, as there are a lot of records to update, i think)

Usually it works correctly when you create/destroy a single object, but having a lot of them it collapsed, i don't know if maybe because the db (mysql), the plugin or what else :)

Just an OT question, do you think that there would be problems having a lot (1-2 millions) of children under a single root?
I mean, about updates and stuff like that... if you add/destroy a child at the start and it has to update thousands/millions of rows with the new lft/rgt i think it would take quite a lot (and we know that users hate to wait too long :( )

Thanks for the report. I haven't moved to Rails 2.3.4 yet, so haven't come across this. Not sure when I will - probably in the next couple weeks, but that's about as best a guess as I have right now. I suggest submitting a patch (or if you fork and fix, do a pull request).

Oops, re-opening, didn't mean to close.

Is this still an issue, or is it resolved by the syntax error in the model file?

Fixed. Thanks for your help.