MySQL Database connection class, function not returning any results

Question

I am currently working on a small project and, for the love of god, I cannot get this PHP class working.

The problem is, doQuery doesn't return anything nor modifies the DB when I type and INSERT or any other command here, always returns false even when called from within the class.

class CONN {

    private $connection;

    public function __construct() {

        $this->connection = new mysqli($address, $user, $pass, $db);
        if ($this->connection->connect_error) {

            // Throw error here
        } else {
            $this->doQuery("SET NAMES 'utf8'");
        }
    }

    public function doQuery($query){

        return $this->connection->query($this->connection->real_escape_string($query));
    }
}

Solved
The real_escape_string escaped even ' and hence the query could not work.

Instead of returning immediately, query for the error if the result is false and log it. Not enough information here by itself. — BaseZen
– BaseZen, Commented Mar 6, 2015 at 19:57
You should only use the real_escape_string on variables used inside the SQL query. I think the quotes around the utf8 are getting escaped and as a result the query is invalid. Is there any errors emitted? — AnotherGuy
– AnotherGuy, Commented Mar 6, 2015 at 19:57
You should consider adding echo $this->connection->error; inside if condition as if($this->connection->error_no){ You will get the exact message if the query fails. You can paste that error here and that can get a clue. — art-fan-vikram
– art-fan-vikram, Commented Mar 6, 2015 at 20:00

taxicala · Accepted Answer · 2015-03-06 20:00:20Z

2

I don't think your code will ever work like that, the main issue i see is the following piece of code:

$this->connection = new mysqli($address, $user, $pass, $db);

Where do $adress, $user, $pass, $db come from? Maybe you missed your constructor arguments.

answered Mar 6, 2015 at 20:00

taxicala

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1 Comment

DragonCz Over a year ago

I just replaced my info with vars

Peter · Accepted Answer · 2015-03-06 20:44:32Z

1

Use real_escape_string only for escaping variables (usually submitted by users) e.g.

$this->doQuery("SELECT * FROM table WHERE something='".$this->connection->real_escape_string($_POST['data'])."'"

do not escape whole query

public function doQuery($query){
    return $this->connection->query($query);
}

answered Mar 6, 2015 at 20:44

Peter

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Comments

David Demetradze · Accepted Answer · 2015-03-06 20:22:41Z

You need to create/provide additional class arguments. When object is created class consructor needs those values to make a connection. So:

class Con
{
    private $address;
    private $username;
    private $password;
    private $database;
    public function __construct($address, $username, $password,$database)
    {
        $this->address = $address;
        $this->username = $username;
        $this->password = $password;
        $this->database = $database;
    }
    public function connect()
    {
        $con = mysqli_connect($this->address, $this->username, $this->password, $this->database);
        return $con;
    }
}


$conobject = new Con("localhost","root","","mybase");
$convar = $conobject->connect();

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