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kevindougans 2 Junior Poster

16 Years Ago

For anyone still using the old "mysql_fetch_assoc" here is something I've just discovered today after about 9 years of PHP'ing and thought I should sahre because I've not seen many open source projects use it (maybe for another reason I'm not yet aware of)...

(note: both provide the exact same output)

if ($no_of_records > 0) {
    $overhead_info = mysql_fetch_assoc($sql_result);
    extract($overhead_info);
}
echo "$rid, $type, $summary, $details, $cost, $purchase_date";


############  instead of  ###############


if ($no_of_types > 0) {
	while ($overhead_type_info = mysql_fetch_assoc($sql_result))
	{
		$rid = $overhead_type_info['row'];
		$type = $overhead_type_info['type'];
		$summary  = $overhead_type_info['summary'];
		$details  = $overhead_type_info['details'];
		$cost  = $overhead_type_info['cost'];
		$purchase_date = $overhead_type_info['purchase_date'];
	}
	echo "$rid, $type, $summary, $details, $cost, $purchase_date";
}

mysql php

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Latest Post 16 Years Ago Latest Post by pbcomput

pbcomput commented: Grt...Hats off...Thanks so much... :) +1

Dani AI

Generated 7 Months Ago

Good, practical tip from — fetching a single associative row and using its fields directly is fine when you truly only need one record. is correct that a loop is required when you expect multiple rows. One modern caveat: the old ext/mysql (the mysql_* functions) was deprecated and later removed from PHP, so new or maintained code should use mysqli or PDO instead. (php.net)

A quick caution about extract() raised by and : it imports array keys into the current symbol table and can overwrite or hide variables; the PHP manual explicitly warns against using extract() on untrusted data. Prefer keeping the row as an array and referencing its keys in your templates, or assign only the variables you need with clear names so the source of each variable is obvious. (php.net)

Practical, modern patterns (PDO example) — prepared statement, single-row fetch, and streaming iteration without loading everything into memory:

$pdo = new PDO('mysql:host=localhost;dbname=app','user','pass',[PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);

// single row
$stmt = $pdo->prepare('SELECT rid, type, summary, cost, purchase_date FROM overhead WHERE id = :id LIMIT 1');
$stmt->execute([':id' => $id]);
$row = $stmt->fetch(PDO::FETCH_ASSOC);
if ($row) { /* use $row['rid'], $row['type'], ... */ }

// iterate many rows (memory-friendly)
$stmt = $pdo->prepare('SELECT rid, type, summary FROM overhead WHERE job = :job');
$stmt->execute([':job' => $jobId]);
while ($r = $stmt->fetch(PDO::FETCH_ASSOC)) { /* render each $r */ }

Use prepared statements to avoid injection and avoid fetchAll() for very large result sets (it can be memory inefficient); stream rows with fetch() instead. (php.net)

Summary: good tip for quick, single-row reads (), but for maintainable, secure code prefer PDO/mysqli prepared queries, explicit variable use (or templating), and streaming fetch for large sets — that keeps code clear and portable across modern PHP versions.

All 14 Replies

urtrivedi 276 Nearly a Posting Virtuoso

16 Years Ago

You can not do anything without loop.
Correct code is as follows

if ($no_of_types > 0) {
	while ($overhead_type_info = mysql_fetch_assoc($sql_result))
	{
		extract($overhead_type_info);
		echo "<br>$rid, $type, $summary, $details, $cost, $purchase_date";
	}

}

Edited 16 Years Ago by urtrivedi because: n/a

urtrivedi 276 Nearly a Posting Virtuoso

16 Years Ago

(note: both provide the exact same output)

I posted because of above quote and just to save newbies from confusion.

logonchristy 0 Light Poster

16 Years Ago

hi kevindougans its nice... Really its useful one...

thanx...

OS_dev 0 Junior Poster

16 Years Ago

I guess what I don't understand is why would someone break up an array into other variables? you already have values in the array. I mean it's cool to know and I didn't even know it existed, I think because I've just never needed it.

Unless, I am working with preexisting code and I need to make a page more dynamic and I don't feel like doing a find and replace, but that would be just lazy.

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kevindougans 2 Junior Poster · Answer 1 · 2010-03-02T16:44:18+00:00

there is no problem with the code if you are only trying to extract the first result or only 1 result. this post was a tip... not a problem :-)

kevindougans 2 Junior Poster · Answer 2 · 2010-03-02T17:05:15+00:00

I posted because of above quote and just to save newbies from confusion.

if there was an edit button i'd ammend it to say "provides exact same output if there's only 1 result". i got too excited and assumed most people would have known what iw as talking about haha

pbcomput 9 Junior Poster in Training · Answer 3 · 2010-03-02T19:48:15+00:00

For anyone still using the old "mysql_fetch_assoc" here is something I've just discovered today after about 9 years of PHP'ing and thought I should sahre because I've not seen many open source projects use it (maybe for another reason I'm not yet aware of)...
(note: both provide the exact same output)
if ($no_of_records > 0) {
    $overhead_info = mysql_fetch_assoc($sql_result);
    extract($overhead_info);
}
echo "$rid, $type, $summary, $details, $cost, $purchase_date";


############  instead of  ###############


if ($no_of_types > 0) {
	while ($overhead_type_info = mysql_fetch_assoc($sql_result))
	{
		$rid = $overhead_type_info['row'];
		$type = $overhead_type_info['type'];
		$summary  = $overhead_type_info['summary'];
		$details  = $overhead_type_info['details'];
		$cost  = $overhead_type_info['cost'];
		$purchase_date = $overhead_type_info['purchase_date'];
	}
	echo "$rid, $type, $summary, $details, $cost, $purchase_date";
}

Grt.....:cool: Thanks for such info....:)

One more thing i want to share that i also tried this wid

mysql_fatch_array()

wel no dought its also working wid this also...:icon_biggrin:

n i already starting to use this one.....:icon_biggrin::icon_cool:

kevindougans 2 Junior Poster · Answer 4 · 2010-03-02T20:10:38+00:00

it really helped me with a current project i've just started working on because of the self made MCV structure they have setup means they use all the column names from the database.

E.g. they have a page to display everything and it's like :

$html_output .=<<<END
			
			  <table style="width: 100%;" cellpadding="5" cellspacing="5" border="0">						
					<tr>
					  <th class="forms_th" style="width: 20%;">Overhead for job:</th>
					  <td style="width: 80%;">$rid</td>
				  </tr>
				  <tr>
					  <th class="forms_th" style="width: 20%;">Unique Overhead ID:</th>
					  <td style="width: 80%;">$eid $quote_ref</td>
				  </tr>
				  <tr>
					  <th class="forms_th" style="width: 20%;">Overhead Type:</th>
					  <td style="width: 80%;">$overhead_type $form_req</td>
				  </tr>
				    <tr>
					  <th class="forms_th" style="width: 20%;">Date:</th>
					  <td style="width: 80%;">$purchase_date</td>
				  </tr>

			  </table>

END;

and then instead of looping through the results and setting each variable I can now just do extract.... simple :-)

ShawnCplus 456 Code Monkey Team Colleague · Answer 5 · 2010-03-02T23:01:08+00:00

Extract is almost always bad practice, especially in the use case provided. Case in point: You worked on some code at a job and it uses extract and you leave the job and someone else comes along and inherits the code. "Hmm, there's this bug involving $somevar but I don't see it defined anywhere..."

3 hours later extract($some_random_array); // I'm awesome "FFFFUUUUUUUU"

kevindougans 2 Junior Poster · Answer 6 · 2010-03-02T23:04:18+00:00

Extract is almost always bad practice, especially in the use case provided. Case in point: You worked on some code at a job and it uses extract and you leave the job and someone else comes along and inherits the code. "Hmm, there's this bug involving $somevar but I don't see it defined anywhere..."
3 hours later extract($some_random_array); // I'm awesome "FFFFUUUUUUUU"

That's why you should comment your code clearly :-)

ShawnCplus 456 Code Monkey Team Colleague · Answer 7 · 2010-03-02T23:08:43+00:00

That's why you should comment your code clearly :-)

Comments or not, extract is by definition obfuscating the initialization of multiple variables. In addition using extract on superglobals (_GET, _POST, etc.) is a massive security risk (You didn't provide this in your example, I'm just pointing out that wanton use of extract is dangerous)

JuanMan 0 Newbie Poster · Answer 8 · 2010-03-02T23:38:25+00:00

Aren't you sure you've misspelled that?

Did you really mean ...

mysql_fetch_array()

Grt.....:cool: Thanks for such info....:)
One more thing i want to share that i also tried this wid
mysql_fatch_array()
wel no dought its also working wid this also...:icon_biggrin:
n i already starting to use this one.....:icon_biggrin::icon_cool:

OS_dev 0 Junior Poster · Answer 9 · 2010-03-03T06:44:12+00:00

That's why you should comment your code clearly :-)

Dude, let me tell you. If I ever used extract in my current position I would feel like an idiot.

Mainly because it automatically doubles your memory usage, that is unless it destroys the array upon doing it. But not only that, it show a lack of understanding in how to use arrays.

pbcomput 9 Junior Poster in Training · Answer 10 · 2010-03-03T15:19:50+00:00

Comments or not, extract is by definition obfuscating the initialization of multiple variables. In addition using extract on superglobals (_GET, _POST, etc.) is a massive security risk (You didn't provide this in your example, I'm just pointing out that wanton use of extract is dangerous)

can u pls tell me y it should b dangerous ?? bcz i started workin like that in my projects...

Thanks..:)

-----

@ JuanMan

Its just a typo...yeah m want to tell that only...

Tip of the Day!

Dani AI

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