php with pdo, create dynamic database connection

Question

I create connection with this statement

dbh = new PDO('mysql:host=localhost;dbname=mydb;port=3306;connect_timeout=15', 'root', '');

But in my application users capable to change data sources so I need to create current database connection with server informations user posted, I try this:

dbh = new PDO('sqlsrv:server=' + $result["servername"] + ';dbname=' + $result["dbname"] + ';port=3306;connect_timeout=15', '' + $result["user"] + '', '' + $result["password"] + '');`

But it failed. Even I tried the simple code examples got documents it fails for that too.. Whats with it and how can I make it ?

Check for $result["dbnamee"], whether it's dbnamee or dbname ? — Happy Coding
– Happy Coding, Commented Aug 31, 2015 at 17:10
@Devon msg: 'PDOException' with message 'could not find driver' in C:\inetpub.. and even I set connection (for next) will it be able to transfer data with created dynamically db ? its my issue desc. thank you — Devs Edition
– Devs Edition, Commented Aug 31, 2015 at 17:20

score 4 · Accepted Answer · 2015-09-01 06:01:25Z

At first, you cant merge strings with '+'. you must use '.' and you need to create new PDO connection object(or set it existing) for each database connection here I share parts of my code doing this:

private function __construct()
    {
        //default database connection
        $this->dbh = new PDO('mysql:host=localhost;dbname=webfilter;port=3306;connect_timeout=15', 'root', '');
        $this->dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $this->dbh->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
        $this->directed = false;
        $this->resultBool = true;
    }

    public static function getConnection()
    {
        $sqlstring = "select * from datasources WHERE ACTIVE =1";
        if (!isset(self::$instance))
        {
            $object = __CLASS__;
            self::$instance = new $object;
        }
        if (true) {
            $request = self::$instance->dbh->prepare($sqlstring);
            if ($request->execute()) {
                if ($result = $request->fetch(PDO::FETCH_ASSOC)) {
                    if ($result["SOFTWARE"] == "mysql") {
                        self::$instance->dbh = null;
                        self::$instance->connectedDbName = "mysql(" . $result["DATABASENAME"] . ")";
                        self::$instance->dbh = new PDO('mysql:host=' . $result["SERVERADDRESS"] . ';dbname=' . $result["DATABASENAME"] . ';port=3306;connect_timeout=15', '' . $result["USERNAME"] . '', '' . $result["PASSWORD"] . '');
                        self::$instance->dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                        self::$instance->directed = true;
                        self::$instance->resultBool = true;
                    } else if ($result["SOFTWARE"] == "mssql") {
                        self::$instance->dbh = null;//close the existing connection
                        self::$instance->connectedDbName = "mssql(" . $result["DATABASENAME"] . ")";
                        self::$instance->dbh = new PDO('sqlsrv:server=' . $result["SERVERADDRESS"] . ';Database=' . $result["DATABASENAME"] . '', '' . $result["USERNAME"] . '', '' . $result["PASSWORD"] . '');
                        self::$instance->dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                        self::$instance->dbh->query("use " . $result["DATABASENAME"]);
                        self::$instance->directed = true;
                        self::$instance->resultBool = true;
                    } else if ($result["SOFTWARE"] == "oracle") {
                        self::$instance->connectedDbName = "oracle(" . $result["DATABASENAME"] . ")";
                        self::$instance->dbh = new PDO('odbc:DRIVER=FreeTDS;server=localhost;Database=Dbname', 'username', '!123qwe');
                    }
                    self::$instance->resultBool = true;
                    $temp = self::$instance->dbh->query("select DEVICEID from ethernet LIMIT 1");
                    self::$instance->setDeviceid($temp->fetchColumn());
                    return self::$instance;
                }
                self::$instance->connectedDbName = "default";
                $temp = self::$instance->dbh->query("select DEVICEID from ethernet LIMIT 1");
                self::$instance->setDeviceid($temp->fetchColumn());
                return self::$instance;
            }
        }
        self::$instance->connectedDbName = "default";
        return self::$instance;
    }

    public function getConnectionStatusMessage()
    {
        if ($this->resultBool) {
            return "Connection Successfull" . $this->connectedDbName;
        } else {
            return "Connection Failed:" . $this->resultString;
        }
    }

trzyeM- · Accepted Answer · 2015-08-31 17:13:24Z

0

$dbh = new PDO('sqlsrv:server=' . $result["servername"] . ';dbname=' . $result["dbname"] . ';port=3306;connect_timeout=15', $result["user"], $result["password"]);

answered Aug 31, 2015 at 17:13

trzyeM-

9638 silver badges10 bronze badges

1 Comment

Tab Alleman Over a year ago

This would be a better quality answer if you gave some explanation of why this code solves the problem.

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