Why is_int on primary key value return string?

Question

I want to check if a member id from a database , is an integer , but when i use is_int function on this data it return me false.. primary key should be an int no?

$query = $sql->prepare("SELECT * FROM `blog` WHERE `categorie` = 'Dossier' ORDER BY `date_ajout` DESC LIMIT  " . $offset . "," . $page_result . "   ");
$query->bindValue(':offset', $offset, PDO::PARAM_INT);
$query->bindValue(':page_result', $page_result, PDO::PARAM_INT);
$query->execute();
$data = $query->fetchAll(PDO::FETCH_ASSOC);
foreach ($data as $key => $value) {
$id = is_int($value['id']);
    var_dump($id);
    echo $id;
}

You need to use `is_numeric` right? ***Note:** To test if a variable is a number or a numeric string (such as form input, which is always a string), you must use `is_numeric()`.* — Praveen Kumar Purushothaman, Mar 23 '16 at 14:04
I tried with is numeric its working , but primary key type is integer so that's why i don't understand. — Trippy, Mar 23 '16 at 14:05
How are you generating the `$value`? Mistake might be there. — Praveen Kumar Purushothaman, Mar 23 '16 at 14:06
Have you checked what `$value['id']` contains, as @Fred-ii- says, dump it and see. — Egg, Mar 23 '16 at 14:06
@Trippy Please put the full code in your question. I am concerned about what and how you are assigning it. — Praveen Kumar Purushothaman, Mar 23 '16 at 14:09
try it without the loop and see what that says on a single pass (in a while loop) for that specific row. You may have other rows in that loop that are not ints. — Funk Forty Niner, Mar 23 '16 at 14:09
@sebastianbrosch Ha ha.. Sorry buddy, I should have not said! :P I too removed my comment! :P — Praveen Kumar Purushothaman, Mar 23 '16 at 14:10
`primary key should be an int no?` - not necessarily; I've used things like ISO codes as primary keys, e.g. ISO 3166 alpha-2 codes for countries. There's no guarantee that your system isn't storing a number in a `CHAR` or `VARCHAR` field. Also depends on your database interface code - what exactly is generating `$data`? — CD001, Mar 23 '16 at 14:13
@Trippy Looks perfect for me. What's your output of `var_dump`? — Praveen Kumar Purushothaman, Mar 23 '16 at 14:17
You're fetching everything from your query, that's why it's failing. If you `SELECT id` you'll see that your `is_int` will be TRUE. — Funk Forty Niner, Mar 23 '16 at 14:17
@Fred-ii- Nopes. Looks alright to me. The `id` gets stored in `id` right? — Praveen Kumar Purushothaman, Mar 23 '16 at 14:18
@PraveenKumar OP's query includes strings and is using `fetchAll(PDO::FETCH_ASSOC)` — Funk Forty Niner, Mar 23 '16 at 14:18
Yes the id is stored in id, my var_dump output string(2)"12" — Trippy, Mar 23 '16 at 14:19
@Trippy Now get back to work. Show us the output of `var_dump()` man. — Praveen Kumar Purushothaman, Mar 23 '16 at 14:19
what you want to do here is a `while` loop (not a foreach) and inside that, `if` and check on that specific row. — Funk Forty Niner, Mar 23 '16 at 14:21
http://stackoverflow.com/questions/5323146/mysql-integer-field-is-returned-as-string-in-php — mitkosoft, Mar 23 '16 at 14:21
I don't see anyone being nasty. Wow, some are just too sensitive. — Funk Forty Niner, Mar 23 '16 at 14:22
Thanx @mitkosoft that's the perfect explanation i was looking for thx — Trippy, Mar 23 '16 at 14:23
possible duplicate of [MySQL integer field is returned as string in PHP](http://stackoverflow.com/questions/5323146/mysql-integer-field-is-returned-as-string-in-php) — Funk Forty Niner, Mar 23 '16 at 14:24
big discussion for nothing :) in general regardless of the data type defined in your tables, PHP's MySQL driver always serves row values as strings. — mitkosoft, Mar 23 '16 at 14:24
@mitkosoft I use the procedural MySQLi and don't use prepared statements, but I get the right data type. Interesting. — Praveen Kumar Purushothaman, Mar 23 '16 at 14:25
Check http://stackoverflow.com/questions/20079320/php-pdo-mysql-how-do-i-return-integer-and-numeric-columns-from-mysql-as-int for a very very detailed explanation. — apokryfos, Mar 23 '16 at 14:56
@mitkosoft - what you wrote isn't true. If `mysqlnd` is installed, then you get appropriate string / int / float types in PHP. If not, then you get strings for everything. However, yes, a big discussion for not so much of a big deal :) — Mjh, Mar 23 '16 at 16:20

score 2 · Answer 1 · edited Mar 23 '16 at 16:08

2

In order for PHP to correctly represent data types from MySQL, you need to have MySQL Native Driver (mysqlnd) installed.

Link: http://php.net/manual/en/book.mysqlnd.php

When you don't have native driver installed, PHP must guess what the type is. The safest type is string.

Function that can determine if a string-representation of something is actually a number is is_numeric.

Alternatively, as you did, you can coerce the type to integer using intval($variable) or (int)$variable.

edited Mar 23 '16 at 16:08

Praveen Kumar Purushothaman

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answered Mar 23 '16 at 14:43

Mjh

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Oh yeah, I do have `mysqlnd` installed. – Praveen Kumar Purushothaman Mar 23 '16 at 16:08

score 0 · Answer 2 · edited Mar 23 '16 at 14:46

0

I found a solution :

if ((is_int($value['id']) != true)) {
  $id = intval($value['id']);
}

Now , it's ok

edited Mar 23 '16 at 14:46

Adam Konieska

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answered Mar 23 '16 at 14:30

Trippy

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Why is_int on primary key value return string?

2 Answers2