Re: proposal: doc: simplify examples of dynamic SQL

On Fri, Mar 20, 2015 at 05:47:49PM -0300, Alvaro Herrera wrote:
> Bruce Momjian wrote:
> > On Fri, Mar 20, 2015 at 08:54:24AM -0700, David G. Johnston wrote:
>
> > > 1. The layout of the format version is different, with respect to newlines,
> > > than the quote version; but while using newlines for the mandatory
> > > concatenation is good having an excessively long format string isn't desirable
> > > and so maybe we should show something like:
> > >
> > > EXECUTE format('SELECT count(*) FROM %I '
> > > || 'WHERE inserted_by = $1 AND insert <= $2', tabname)
> > > INTO c
> > > USING checked_user, checked_date
> >
> > I think that is very confusing --- the idea is that we don't need to use
> > || with format, but you are then using || to span multiple lines.
>
> That || seems fine, since it's only used for a line continuation; having
> || scattered all over the query string to interpolate each variable is
> much more unreadable.
>
> That said, the || there is unnecessary because per standard two literals 'lit1'
> 'lit2'
> are concatenated if they are separated by a newline. So this
>
> EXECUTE format('SELECT count(*) FROM %I '
> 'WHERE inserted_by = $1 AND insert <= $2', tabname)
> INTO c
> USING checked_user, checked_date
>
> should suffice.

OK, I used your idea, patch attached.

> BTW very long lines are undesirable because they are truncated in the
> PDF output.

True, but the length was only 95 characters --- is that too long for our
PDFs?

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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