On Jan 18, 2009, at 2:16 PM, Adam Dziendziel wrote:

>
> On 18 Sty, 19:47, Michael Bayer <[email protected]> wrote:
>
>> However what I cant figure out with nested sets is, how do I load  
>> only
>> the immediate children of a node ?    That is the most common  
>> accessor
>> I'd like on a self referential node and I'm not aware of how to do
>> it.   It makes it sort of impossible for there to be a ".children"
>> accessor on a node, unless you load the full subtree and organize.
>
> It is possible if you add a 'depth' column which holds the absolute
> distance of the node from the tree root.
> Then, in order to load immediate children of a node, we can make a
> query:
>
> SELECT * FROM nodes WHERE lft > node.lft and rgt < node.rgt and
> depth=node.depth+1


yeah, the example is actually illustrating depth query based on a  
count at the end so we use that using HAVING, but here I see you  
actually added depth to the table.   so we might add examples for both  
methods.

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