From: Don Parris [mailto:[email protected]]
Sent: Tuesday, February 26, 2013 1:23 PM
To: Misa Simic
Cc: Igor Neyman; [email protected]
Subject: Re: [SQL] Using Ltree For Hierarchical Structures
Hi Igor,
As Misa points out, my original design used 2 tables - category & line-items.
Either way it's two tables. The biggest difference lies in the approach to
summing line-items by various levels of category - with each branch of the tree
having different levels.
I cannot speak to performance, but understanding CTEs has been difficult for
me. Ltree is so much simpler. I am certain there is a place for CTEs, but why
torture myself trying to hash out a CTE when ltree makes the queries so much
easier to write?
Don,
To answer this question...
Before I worked (mostly) with Oracle which has "connect by" construct to work
with hierarchies.
So, when I switched to Postgres I was happy to find "connect_by" contrib. modul.
And with more recent PG versions, it was just natural transition from contrib.
module to recursive CTEs.
Igor
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