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HTMLHelp Forums _ Databases _ By which specific command does PDO queries a database. Apart from $db ?

Posted by: xcislav Apr 8 2014, 04:55 PM

$db is a variable and from (instruction/command/operator) perspective it's dead and non-wonking.

All documentation which I googled is vague. It does not say explicitly:
Solely set $db makes an sql query.

For example I have one working code which greps a table from my DB:

CODE
<?php $db=new PDO('mysql:host=localhost;dbname=test;charset=utf8', 'root', 'hyuiuik'); foreach($db->query('SELECT * FROM TABBL') as $value) { echo $value['nn']; }


foreach seems to be this instruction.

I'm doing all this to build a voting system with like button (in js/php(pdo)/mysql(txt) - minimal implementation.
This plus one ("+1") "like button"-voting system which i want to have the maximum minimalist approach (no auth non-voting non-login). Just 1. Press - HTML/Javascript
<input type="button" id="like" onClick="like1()" value="+1">
<script>
function like1 {
like.value += 1
}
</script>
2. Send PHP (PDO!) 3. Receive Textfile (may be.. mysql) *it has to be as simple as it could be* 4. Show +1, which would be visible to other visitors (ajax/js - optional). That example to be working. I have mysql and apache and php PDO (php5.5.6)! (I've googled this http://lanother.tk/likebutton.html - complex)


And if I solve this PDO issue - it will be very important.

Posted by: xcislav Apr 15 2014, 06:26 AM

Post is self-answered.

CODE
<?php $db=new PDO('mysql:host=localhost;dbname=test;charset=utf8','$us','$ps');$db->exec("UPDATE TXT SET cn=cn+1");$rs=$db->query("SELECT cn FROM TXT");print_r($rs->fetchColumn());?>


The answer is: PDO queries a database of SQL/SELECT by $db->query
via an object-assignment procedure. $rs=
So print_r($rs->fetchColumn()) finally retrieves THE SELECTION as a minimal possible approach.
fetchColumn in this case is more specific (and focused) than the whole set (the set is retrieved from database as an array).


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