Creating $_POST array

PHP
1

In my forms, my fields look like this:

City: <input type=“text” name=“city” value=“<?php echo $_POST[‘city’]?>”>

That way, the fields automatically persist when the user’s input has an error and the form must be corrected and resubmitted. This works fine when adding records.

However, when updating an existing record, there is no $_POST array yet when the form is first displayed. So you do something like this:

$query = ‘SELECT * FROM mytable WHERE id LIKE "’ . $_GET[‘id’] . ‘’';
$result = mysql_query($query);
$fields = mysql_fetch_assoc($result);

and you change your form fields to look like this:

City: <input type=“text” name=“city” value=“<?php echo $fields[‘city’]?>”>

But now you have to move array contents between $_POST and $fields because when the user edits and submits the form, the updated info is going to $_POST, not $fields. The only way to update the display is to copy the values from $_POST to $fields.

What if instead we fetched the record directly into the $_POST array, like this?

$query = ‘SELECT * FROM mytable WHERE id LIKE "’ . $_GET[‘id’] . ‘’';
$result = mysql_query($query);
$_POST = mysql_fetch_assoc($result);

That way, there’s no need to use a separate array with whatever complexity it adds. But I’ve looked all over google, and I’ve only found a couple of examples using $_POST that way, so I figure there must be something wrong with it. Is creating the $_POST array like this bad practice? Does it confuse the PHP internals somehow? It seems to work, though.

2

What about:

City: <input type="text" name="city" value="<?= ($_POST['city'] != NULL) ? $_POST['city'] : $fields['city']; ?>">

Uses the post value, if it exists, otherwise uses the array value.

I’ve never used post in the way you mentioned. Not sure if it’s considered bad practice or not, but I can’t imagine it is.

3

Instead of using the POST array directly use an array of the field values. That way you can swap the values in and out based on an edit or create using the same interface.


<?php $values['foo'] = $_POST['foo']; ?>

<?php /* .. template .. */ ?>
<input type="text" name="foo" value="<?php echo $values['foo']; ?>">

I would advise against the method cydewaze described because it not only introduces unnecessary logic into the presentation layer but lacks flexibility for making future changes. Not to mention it introduces another layer of complexity for designers that may need to modify the template to achieve a specific design goal. Also, the relationship between the domain and database is not always the same. For maximum flexibility consider the likely possibility of supporting abstracted database values.

4

These two posts bring up an interesting point - when is it too early to start talking about design patterns and things like “presentation” layer?

Cyde’s solution isn’t bad I think when someone is just starting to learn PHP. But in a large scale application where a design pattern is used to help maintain the software it would be verboten.

I mean, there is a limit to how much you should spring on someone who’s starting off. Introducing MVC on day one is a bit much in my opinion.

5

Design patterns are not synonymous with separation of logic and content. A design pattern is essentially a problem analyzed.

Separation of logic and modularity of code are not MVC topics. But rather, concepts that should be taught at a beginner level.

I do agree with oddz, in that the previous solution introduces unnecessary verbosity.

6

I’m going to fork to another thread. This promises to be a fun topic for a few days.

7

Which would be me! :smiley: Thus, my newb solution. :slight_smile:

8

Ok, I won’t do $_POST = mysql_fetch_assoc, though I’m thinking it doesn’t corrupt anything internal to PHP.

Good point, Michael. Your new thread sounds good.

9

Yeah, I was by no means trying to bring up MVC directly – just provide a quick tip for making maintenance and further development a little less painful (hopefully).