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Re: libpq: NULL in binary parameters

From: Andrew McNamara <andrewm(at)object-craft(dot)com(dot)au>
To: john heasley <heas(at)shrubbery(dot)net>
Cc: pgsql-interfaces(at)postgresql(dot)org
Subject: Re: libpq: NULL in binary parameters
Date: 2007-05-17 23:11:39
Message-ID: 20070517231139.80666600895@longblack.object-craft.com.au (view raw or flat)
Thread:
Lists: pgsql-interfaces
>Using binary parameters with libpq (PQexecParams) I am having trouble
>figuring out how NULL is represented since there does not appear to be
>a NULLOID.
>
>For example, if a table has a varchar column and it IS NULL for a given
>row, then what I received is a zero-length string ("").  Also, while I
>can insert a NULL varchar simply by setting the value to NULL (or 0), it
>is not clear how to acheive this with say an integer column.  And, is it
>possible to match NULL using a parameter.

The arguments to PQexecParams are all pointers to buffers, even in the
case of ints. To send a NULL, simply pass a null pointer for that value.

-- 
Andrew McNamara, Senior Developer, Object Craft
http://www.object-craft.com.au/

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