Getting information from MySQL - php

Question

I'm having trouble getting info from my MySQL database.
Here is my code :
/********************
* Database Info
********************/
$host = "localhost";
$user = "admin";
$pass = "admin#";
$database = "db_admin";
/********************
* Database connection
********************/
$con = mysqli_connect( $host, $user, $pass, $database );
if (mysqli_connect_errno ()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error ();
}
$result = array();
if (isset($_POST['ID'])) {
$id = $_POST['ID'];
$query = "SELECT * FROM Servers WHERE PID='" .$id. "'";
$result = mysqli_query($con, $query);
}
print("<pre>".print_r($result,true)."</pre>");
My first question, Did I use "isset" function currectly?
Because it doesnt seem like it is actually going though the if statement.
The Url I am using is : #..com/view.php?ID=1
My second question, Did I use the $query correctly?
Because I echo $id and that echoed out a "MySQL Object()"
Finally, the print printed out "Array()"
I'm just starting on PHP, Thanks for the help :)

Answer 1

A few things:
If you're passing the variable in the query string, use $_GET instead of $_POST to retrieve the values.
$result will return an pointer to the recordset, not the rows themselves. You will have to use mysqli_fetch_array() to fetch the rows.
ADD:
If you are sure that you will only have 1 record returning, you can use:
$row = mysqli_fetch_assoc($query);
echo $row['field_name'];
More then 1 record?
while($row = mysqli_fetch_assoc($query)){
echo $row['field_name'];
}

Answer 2

# your first question: if you have a input field with the name="ID", then its good.
Please also post your HTML :)
$var = 'Hello world';
if(isset($var)){ //If the var $var has been set (in this case it is)
echo $var;
} else {
//If $var is not set, then we get in the else
echo 'The var $var is not set';
}

Answer 3

The best thing is debugging the code with a debugger, you may use XDebug, or at least use var_dump(); to see what happens
var_dump($_REQUEST, $result);

Answer 4

Answer to your first question: It's hard to say if you've used it correctly when you haven't said what you're trying to do. I'm presuming that you only want run the code enclosed in the if-statement if the POST variable 'ID' has been received. If so, yes you've done it correctly.
Answer to your second question: I'm presuming on this line you're trying to build a string with a valid MySQL query. You've done that correctly, assuming $_POST['ID'] is a string (or can be converted to a string, see http://www.php.net/manual/en/language.types.string.php#language.types.string.casting).
If you're echoing $id and it's returning an object, however, you'll have a problem. You can't combine a string and an object like that. You'd need to iterate the object with a foreach, for example, and extract the id from that. The rest of the code won't work until that part is resolved.
The thing to investigate now is why $_POST['ID'] is returning an object. You'll need to provide the form code at the very least.