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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