Re: pg_restore casts check constraints differently

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Amit Langote <amitlangote09(at)gmail(dot)com>
Cc: Joshua Ma <josh(at)benchling(dot)com>, PostgreSQL mailing lists <pgsql-general(at)postgresql(dot)org>, Victor Pontis <victor(at)benchling(dot)com>
Subject: Re: pg_restore casts check constraints differently
Date: 2016-03-30 14:01:35
Message-ID: 395.1459346495@sss.pgh.pa.us
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Amit Langote <amitlangote09(at)gmail(dot)com> writes:
> destdb=# ALTER TABLE c ADD CONSTRAINT p_a_check CHECK (a IN ('a', 'b', 'c'));
> destdb=# \d c
> ...
> Check constraints:
> "p_a_check" CHECK (a::text = ANY (ARRAY['a'::character varying,
> 'b'::character varying, 'c'::character varying]::text[]))

Hm. It seems like the parser is doing something weird with IN there.
If you just do a simple comparison the constant ends up as TEXT to start
with:

regression=# CREATE TABLE pp (a varchar, CHECK (a = 'a'));
regression=# \d pp
...
Check constraints:
"pp_a_check" CHECK (a::text = 'a'::text)

Or for that matter

regression=# CREATE TABLE p (a varchar, CHECK (a = any(array['a', 'b', 'c'])));
regression=# \d p
...
Check constraints:
"p_a_check" CHECK (a::text = ANY (ARRAY['a'::text, 'b'::text, 'c'::text]))

I wonder why you don't get an array of text constants in the IN case.

regards, tom lane

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