Re: Tree structure

> 1. As strings
> There's no dedicated function (@>)
> WHERE clause should read something like 'a/b/c/d' LIKE column || '%',
> which is both ugly and (I guess) non indexable
> Perhaps regex indexes would work, but not efficient and not optimal
>
> 2. As array of strings
> My favorite, would be elegant. A GIN index on the whole array would make
> for fast performance
> Alas @> treats the arrays as a set, not an array
> WHERE col @> 'a/b/c/d' would find all of the above rows, including a, a/c,
> b/a, etc.
>
> 3. ltree contrib
> The only option that actually works and uses index
> @> works as I want it to.
> But the single segments can only be alphanumeric and underscore
> ltree only supports GIST
> there's a length limit.

4. Using a recursive common table expression (CTE).
http://www.postgresql.org/docs/9.2/static/queries-with.html

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