On Tue, 2002-02-12 at 19:53, Ola Sundell wrote:
> Recently I found an Oracle extension, START WITH .. CONNECT BY, which
> greatly eases parsing of n-way tree structures stored in table format.
>
It's in TODO as WITH RECURSIVE, which is the SQL3 way of doing it, but I
don't know if anyone is seriously working on it.
I have done a little investigation, and I think that this could be
doable without too much changes in planner/executor by doing repeated
merge or hash joins.
If we want automatic checks for infinite recursion there are also two
ways of doing it: 1) use a has of already selected rows or 2) pick new rows from a realize'd table and mark them as
removed there.
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Hannu
