Passing JS-array to PHP, then updating MySQL

Question

I have a problem. The story so far:

PHP1 reads an array from the database, that contains only integers - it has the following form:
[0, 70, 44, ...]

Because the number of entities it contains varies, I want to be able to read and store the whole array into one cell of the database - the solution must not disregard this, then.

PHP1 contains some JS, that allows a user to do something on the website, which alters one of the entities in the array, which makes it, e.g.;
[0, 75, 44, ...]

So far, so good.

Now I want this new array to replace the one in the database, this is the central goal that I fail to achieve.

What I'm currently working with - which isn't working:

PHP1 executes some AJAX magic, and sends this array to PHP2, which works fine:

var arrayX = [0, 75, 44, ...];
var arrayY = JSON.stringify(arrayX);

$.ajax({
    url: 'PHP2.php',
    type: 'post',
    data: {arrayY: arrayY }
});

PHP2 then connects to the DB, and attempts to update that one cell with the new array, by means of the following, which doesn't work (!):

$arrayZ = json_decode($_POST['arrayY'], true);

mysql_query("UPDATE userbase SET db_column = $arrayZ WHERE id=0", $con);

mysql_close($con);

I've tried serializing $arrayZ in PHP2, as well as a whole set of other solutions I found on Stackoverflow, but none of them worked (or I didn't apply them correctly of course) and now I've found myself deadstruck...

I'm hoping your talents will get me further than my own have!

Your database schema is flawed - having multivalued cells is a horrible idea. — Fake51
– Fake51, Commented Jul 17, 2013 at 14:13
"dont work" is not much...please provide more informations why it is not working — Michael Walter
– Michael Walter, Commented Jul 17, 2013 at 14:13
please do a print_r($_POST); at the top of PHP2 and post your output here. — steven
– steven, Commented Jul 17, 2013 at 14:14
it seems that you dont need to JSON.stringify because its already json — steven
– steven, Commented Jul 17, 2013 at 14:15
Steven, this is what I get: Array ( [arrayZ] => [1,70] ) Warning: Cannot modify header information - headers already sent by (output started at .../PHP2.php:3) in .../PHP2.php on line 5 Warning: session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cache limiter - headers already sent (output started at .../PHP2.php:3) in .../PHP2.php on line 7 — Victor
– Victor, Commented Jul 17, 2013 at 14:39

Fotiman · Accepted Answer · 2013-07-17 14:17:42Z

3

I assume db_column holds a string value, and as such you probably just need quotes around $arrayZ in your SQL string.

mysql_query("UPDATE userbase SET db_column = '$arrayZ' WHERE id=0", $con);

But as Fake51 pointed out, your database schema is flawed.

Also, you're susceptible to a SQL Injection attack.

answered Jul 17, 2013 at 14:17

Fotiman

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2 Comments

Victor Over a year ago

then the DB contains only 'array', instead of the actual array.

tadman Over a year ago

@victor Create a one-to-many relationship to store these values. What you're doing here is a bad idea.

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