Why is my PDO not working? - php

Question

I am starting to use PDO and I successfully connected to MySQL using PDO. However, when I try to SELECT stuff from my DB, nothing happens. Nothing is echoed. (even though I have records in that table, and the column username exists) No error in my PHP log.
I am using MAMP and all PDO components seem to be working in phpinfo() (since I was able to connect to db in the first place)
Please let me know what could have gone wrong. Thanks a lot
<?php
try
{
$connection = new PDO('mysql:host=localhost;dbname:my_db','my_username',
'xxxxxxx');
$stmt=$connection->prepare("SELECT * FROM users");
$stmt->execute();
while ($row=$stmt->fetch(PDO::FETCH_OBJ)){
echo $row->username;
}
}
catch(Exception $e)
{
echo "There was an error connecting to the database";
}
?>

Answer 1

You need to tell PDO that you want it to throw exceptions:
$connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
Following your comment below, it is apparent that your DSN is incorrect. It should be:
$connection = new PDO('mysql:host=localhost;dbname=my_db','my_username','xxxxxxx');
Note that the syntax is dbname= rather than dbname: (which you had originally).

Answer 2

First, get your query out of your PDO connection segment...
<?php
try
{
$connection = new PDO('mysql:host=localhost;dbname:my_db','my_username',
'xxxxxxx');
}
catch(Exception $e)
{
echo "There was an error connecting to the database";
}
?>
Then, do it.
<?php
$SQL = 'SELECT * FROM users';
foreach($connection->query($SQL) as $row){
print $row['username'] . "\n".'<br />';
}
?>

Answer 3

Why not ask PHP?
catch(Exception $e)
{
die($e);
}

Answer 4

Looks like your either don't have data in that table or have an error:
Try to add this code after $stmt->execute();:
$arr = $sth->errorInfo();
print_r($arr);