On 31/07/11 21:36, Alban Hertroys wrote:
On 30 Jul 2011, at 13:49, Gavin Flower wrote:
On 30/07/11 10:45, bricklen wrote:
[...]
CREATE OR REPLACE VIEW table_dependencies AS (
WITH RECURSIVE t AS (
SELECT
c.oid AS origin_id,
c.oid::regclass::text AS origin_table,
c.oid AS referencing_id,
c.oid::regclass::text AS referencing_table,
c2.oid AS referenced_id,
c2.oid::regclass::text AS referenced_table,
ARRAY[c.oid::regclass,c2.oid::regclass] AS chain
FROM pg_catalog.pg_constraint AS co
INNER JOIN pg_catalog.pg_class AS c
ON c.oid = co.conrelid
INNER JOIN pg_catalog.pg_class AS c2
ON c2.oid = co.confrelid
[...]
I am curious about the explicit use of INNER JOINs, I find them cumbersome, so I rewrote the code to remove them, I know in some situations that they can improve performance - but was this the case here, or is there some other subtlety that I have missed?
Explicit inner joins provide a means to separate the join conditions from other result filtering conditions. Each join is kept with its relevant conditions even, so it's immediately clear which conditions pertain to which joins.
I find in general explicit inner joins improve readability of queries over implicit joins, especially when the joins get a little more complicated.
Perhaps what you find cumbersome about them is just a matter of formatting?
Alban Hertroys
[...]
Formatting, and habits gained before I fully realized the
significance of explicit inner joins. I appreciate your answer
(keeping the joins separate from the filter conditions) - I
think I might adopt the same approach, though I hate the
cumbersome formatting.
Q. What is the difference between an Experienced Developer and a
Trainee?
A. An Experienced Developer makes mistakes
at a faster rate!
(Or am I being to cynical???)
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