From: Adam Witney <awitney@sghms.ac.uk>
To: David Wheeler <david@wheeler.net>
Cc: dbi-dev@perl.org, pgsql-interfaces <pgsql-interfaces@postgresql.org>
Subject: Re: :PgSQL: More Queestions
Date: Thu, 21 Nov 2002 10:53:32 +0000
Message-ID: <BA026BAC.BF01%a.witney@sghms.ac.uk> (raw)
In-Reply-To: <289E1136-FC56-11D6-8F04-0003931A964A@wheeler.net>
> I understand that the goal is to convert the placeholders from '?' or
> ':nn' to the PostgreSQL internal version (':pn'). What I'm referring to
> specifically, however, is this snippet from DBD::Pg:
>
> if (in_literal) {
> /* Check if literal ends but keep quotes in literal */
> if (*src == in_literal) {
> int bs = 0;
> char *str;
> str = src-1; /* Back a character. */
> while (*(str - bs) == '\\')
> bs++;
> if (!(bs & 1))
> /* bs is an even number? */
> in_literal = 0;
> }
> *dest++ = *src++;
> continue;
> }
>
> in_literal is set when the last character wasn't a placeholder
> character ('?' or ':') and is either a single or a double quotation
> mark. So while I understand that one might want to ignore placeholder
> characters, I don't really understand what the above code is doing.
> Probably'll be easier for me after I've been looking a C for a while...
One thing you may want to keep in mind is the situation concerning array
slices
If you send a statement like this
my $sth = $dbh->prepare("select cube[1:2][1][1] from test4");
Then the :2 gets treated as a placeholder and gets substituted. From the
trace
dbd_st_execute: statement = >select cube[1NULL][1][1] from test4<
ERROR: parser: parse error at or near "NULL" at character 14 error 7
recorded: ERROR: parser: parse error at or near "
NULL" at character 14
As no parameters have been bound to the placeholder then a NULL is
substituted and so it fails.
Or maybe I was doing it wrong and there is a way to get around this already?
Thanks
adam
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To: pgsql-interfaces@postgresql.org
Cc: awitney@sghms.ac.uk, david@wheeler.net
Subject: Re: :PgSQL: More Queestions
In-Reply-To: <BA026BAC.BF01%a.witney@sghms.ac.uk>
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