What is wrong with this update statement?

Here's my code:

$jorja="update features set featurename='$_POST[feature_name_'.$vivian_row[id]]' where id=$vivian_row['id']";

The error I get is "Parse error: syntax error, unexpected '' (T_ENCAPSED_AND_WHITESPACE), expecting ']' in C:\wamp\www\kitchen\adm\features_edit.php on line 20"

I don't see what the problem is...
brucegustPHP DeveloperAsked:
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Ray PaseurConnect With a Mentor Commented:
There are several problems here, but nothing that can't be simplified and corrected easily.

If you're making reference to $_POST in a query string it almost certainly means your script is vulnerable to external attacks.  You probably want to use MySQLI::real_escape_string() or a similar "minimum-level" method to sanitize the external data.

If you're using an associative array index without quotation marks, you're at risk that a defined constant could cause a name collision, and in any case, your code will raise an unwanted Notice message.  Learn more about how PHP quotes and apostrophes work here.
https://www.experts-exchange.com/articles/12241/Quotation-Marks-in-PHP.html

If you're using compound statements, you're writing code that is brittle and hard to debug.  This is probably the source of the parse error -- it's difficult to see where the quote marks are supposed to go in compound statements and arguments.  So just don't do that!  You can make this easier on yourself by writing simple, unit-level statements.  Please see AntiPractices 9 and 9a.

Here is how I might do it.  You can create different variables, and each of these variables can be fed to var_dump() so you can see what the variable(s) contain.  Much easier than guessing whether your syntax is correct!  For links to the PHP var_dump() man page, please refer back to your recent questions.
// ISOLATE vivian_row id 
$vrid    = $vivian_row['id'];
$ok_vrid = $mysqli->real_escape_String($vrid);

// ISOLATE POST-REQUEST feature_name_
$pfid    = 'feature_name_' . $vrid;
$ok_pfid = $mysqli->real_escape_String($pfid);

// CONSTRUCT THE QUERY -- DO YOU WANT A TABLE SCAN, OR SHOULD YOU CONSIDER USING A "LIMIT 1" CLAUSE??
$jorja   = "UPDATE features SET featurename='$ok_pfid' WHERE id='$ok_vrid'";

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brucegustPHP DeveloperAuthor Commented:
I made this change:

$jorja="update features set featurename='$_POST[feature_name_'.$vivian_row['id'].']' where id='$vivian_row[id]'";

Same error.

What?
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Guy Hengel [angelIII / a3]Connect With a Mentor Billing EngineerCommented:
$jorja="update features set featurename='" . $_POST['feature_name_'.$vivian_row[id]] ."' where id=$vivian_row['id']";
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Scott Fell, EE MVEConnect With a Mentor Developer & EE ModeratorCommented:
NO POINTS

While I am sure Guy's code is good and meets your needs for the purpose of this question, you should really sanitize your data before updating.    Updating or adding raw posted and concatenated data to your database is not very safe.

At the very least, sanitize http://php.net/manual/en/filter.filters.sanitize.php and use an abstraction if you are not already http://php.net/manual/en/intro.pdo.php


$feature_name = $_POST[feature_name];
$new_feature_name = filter_var($feature_name , FILTER_SANITIZE_STRING).$vivian_row[id];
$jorja="update features set featurename='" . $new_feature_name  ."' where id=$vivian_row['id']";
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Vatsal ShahConnect With a Mentor Full Stack Expert Web DeveloperCommented:
Please Try Below Code.
$jorja="update features set featurename={$_POST['feature_name_'.$vivian_row['id']]} where id=".$vivian_row['id'];

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Regards,
Vatsal
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Ray PaseurCommented:
To anyone coming across this in the future, the "assisted solution" from Vatsal Shah perpetuates one of the many dangerous practices that novice PHP programmers often follow without understanding the risks.  

Do not use unfiltered values from any external variable (in this case $_POST) in a query string.
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Vatsal ShahFull Stack Expert Web DeveloperCommented:
Hey Ray Paseur,

Yes, You are Right to not to send anything directly from user.
But here the issue was with update query, so just gave him solution.
Otherwise it is common practice to validate, sanitize, etc.

Thanks.
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