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Date: Fri, 2 Oct 2015 10:43:17 +0100
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To: Rowan Collins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] PHP 7.1 - Address PHPSadness #28?
From: craig@craigfrancis.co.uk (Craig Francis)

While skim reading emails (just got back from holiday), I wanted to =
add...


On 23 Sep 2015, at 11:40, Rowan Collins <rowan.collins@gmail.com> wrote:

> A non-existent variable, however, is not something I've ever come =
across in a database context - it would seem to require a result set =
having rows with different numbers of columns.


Imagine an admin interface with a table of orders (showing customer =
name, date, link to view details, etc).

Normally a simple SQL query can do this from 1 table (very fast).

But once a month the admin wants to see a new column (maybe checking if =
a particular product was in each order), and that uses a slightly =
different query (joining a second table, which might be very slow to =
execute).

In the view code (assuming no other helper for creating the HTML), it =
would be easier to read the following than using array_key_extists():

<?php if (exists($row['special'])) { ?>
    <td>...</td>
<?php } ?>

Admittedly I would probably use a variable to say if the column will be =
there or not (because there is also the table headers to add).

That said, this probably doesn't really add to the use cases... but =
hopefully gives an example of a non-existent variable in a database =
context.

Craig=