Subject: Re: How to insert default value with libpq?
To: sanpi+postgersql@homecomputing.fr, pgsql-interfaces@lists.postgresql.org
References: <e7a30543-1b9f-b137-253f-ff9cc9aac893@homecomputing.fr>
From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Organization: 2ndQuadrant
Message-ID: <4aad674b-64c1-61d4-42f1-0adb292ee989@2ndquadrant.com>
Date: Tue, 28 Apr 2020 16:25:48 +0200
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On 2020-04-27 15:02, sanpi+postgersql@homecomputing.fr wrote:
> I would like to insert the default value for a field with libpq, but
> inserting null or "default" doesn’t work.

You cannot represent that using query parameters (PQexecParams).  Query 
parameters always mean, use this rather than the default value.

To do what you want either write DEFAULT or leave off the column 
altogether, for example

     INSERT INTO test (id) VALUES (DEFAULT)

but this needs to be pasted into the query string, not passed as a 
parameter.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services