I have read that PHP is obsoleting the MySql functions.
How will we connect to MySql database?
Where did you hear that? I think it would be a great idea, but it's news to me.
It's better to use new mysqli('hostname', 'username', 'password', 'database')
Or (even better) use new PDO('mysql:dbname=database;host=hostname', 'username', 'password')
Using the new MySQLi classes.
The new, better way of doing it is to use PDO. You can find pretty of examples on the web if you Google for "php mysql pdo", here is one.
Using PDO (PHP Data Objects)
example.
$dsn = 'mysql:dbname=testdb;host=127.0.0.1';
$user = 'dbuser';
$password = 'dbpass';
try {
$dbh = new PDO($dsn, $user, $password);
}
catch (PDOException $e) {
echo 'Connection failed: ' . $e->getMessage();
}
Related
I CAN'T USE MYSQLI OR PDO
I'm currently working on a legacy project (5.2) where I can't use fancy extensions like MySQLi or PDO - Only MySQL - How would I connect to a database and use that connection in a class?
Basically this
public function __construct($pdo) {
$this->db = $pdo;
}
As 5.2 MySQL / PHP
I just need a simple example to get started.
Thanks!
PDO Connection through PHP
I highly recommend to use PDO rather than mysqli.. pdo is faster and use prepared statements to avoid sql injection, and Filter, Sanitize the user inputs.
<?php
session_start();
$servername = "localhost";
$username = "username";
$password = "password";
// Create connection
$conn = new mysqli($servername, $username, $password);
// Check connection
if (mysqli_connect_error()) {
die("Database connection failed: " . mysqli_connect_error());
}
echo "Connected successfully";
?>
You can use the above code for PHP 5.2.9 and 5.3.0
I am trying to get results from an API call using Slim connecting with MSSQLSERVER2012
the example used to work with MYSQL getconnection function (see below) but when I am trying to
connect with MsSQL server 2012 I am getting an error like "api call error "invalid data source name"
http://localhost/msapi/api.php/clients
1'api call error "invalid data source name"
require '/Slim/Slim.php';
$app = new Slim();
$app->get('/clients', 'getClients');
$app->run();
function getClients() {
$sql = "select * FROM clients";
try {
$db = getConnection();
$stmt = $db->query($sql);
$clients = $stmt->fetchAll(PDO::FETCH_OBJ);
$db = null;
echo '{"client": ' . json_encode($clients) . '}';
} catch(PDOException $e) {
echo '{"error":{"text":'. $e->getMessage() .'}}';
}
}
function getConnection_MYSQL() {
$dbhost="SERVER";
$dbuser="USER";
$dbpass="PASSWORD";
$dbname="DB";
$dbh = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbuser, $dbpass);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
return $dbh;
}
function getConnection() {
$dbhost="SERVER";
$dbuser="USER";
$dbpass="PASSWORD";
$dbname="DB";
$dbh = new PDO ("ADODB.Connection");
$connStr = "PROVIDER=SQLOLEDB;SERVER=".$dbhost.";UID=".$dbuser.";PWD=".$dbpass.";DATABASE=".$dbname;
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$dbh->open($connStr); //Open the connection to the database
return $dbh;
}
the function getConnection_MYSQL() is an example that works.
But the getConnection() tryis to connect with MS SQL server ?
Do you see why I am getting an "invalid data source name" with the function getConnection()?
Since you didn't post an alternative DSN-string, I'm assuming you are using the one from your example and just replace host, username and password. This won't work.
When you are running your Slim-application on a windows host you can (and should) use Microsoft's SQL Server Driver for PHP (sqlsrv).
There are 2 versions sqlsrv.dll and pdo_sqlsrv.dll. When you want to reuse most of your code you should use the latter. This way you probably only have to modify your DSN (see php docs):
new PDO("sqlsrv:Server=localhost;Database=testdb", "UserName", "Password");
If you are using the first you have to update the way you connect to the db and create the query. You can read the Beginner's Guide to see a few examples that should make it easy.
If you are running not running your application on a Windows-machine you will probably have to set up ODBC and FreeTDS and then use PDO with an ODBC-DSN. From my experience this will be quite a lot of work, but there are a few good tutorials out there. Just google for "freetds sql server".
I am thinking, is it safe and OK to use db connection in function to return it anywhere in the project? If I want to reuse this project to build another one, I can change db connection only in this function and I don't need to go all over the script searching and changing connection parameter.
function connect_db(){
$db = new PDO('mysql:host=localhost;dbname=;charset=utf8', '', '');
return $db;
}
Now I can call it anywhere functions.php file is required once, by returning
$db = connect_db();
and then whatever statement follows.
Is it ok and safe?
And how to close connection like this at the end of the page?
$db = NULL;
apparently won't work.
Yes, it is safe and ok to have a single place that creates a connection to your database. I would change your function just a bit though:
<?php
function connect_db(){
try{
return new PDO('mysql:host=localhost;dbname=mydb', 'username', 'password', array(PDO::MYSQL_ATTR_INIT_COMMAND =>'SET NAMES utf8'));
}catch (PDOException $e){
echo '<p>Error connecting to database! ' . $e->getMessage() . '</p>';
die();
}
}
?>
You can read more about the PDO constructor in the documentation.
And to close the PDO connection created this way you do indeed just:
<?php
$pdo = NULL;
?>
Please note that there is really a lot more to be said on this subject. Ideally you would have a class that handles the creation of your PDO object(s). You might want to take a look at this excellent answer from Gordon as a place to start.
This question already has answers here:
How to properly set up a PDO connection
(5 answers)
Closed 9 years ago.
Okay so I have some what of a dumb question, I've seen tuts and different things on making a CMS and I want to make an oop CMS, and I was wondering if someone could explain to me what the difference was between using one of the two examples?
Ex 1 -
class myClass
{
var $username;
var $password;
public function connect()
{
try {
$pdo = new PDO('mysql:host=localhost;dbname=dbname', $this->username,
$this->password);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
return $pdo;
} catch(PDOException $e) {
echo 'Error: ' . $e->getMessage();
}
}
}
// Then to call that function
$obj = new myClass();
$obj->username = "root";
$obj->password = "password";
$pdo = $obj->connect();
// Then run my query down here
Ex 2 -
class database
{
protected $connection = null;
//make a connection
public function __construct($hostname,$dbname,$username,$password)
{
try {
//MySQL with PDO_MYSQL
$this->connection = new PDO("mysql:host=$hostname;dbname=$dbname",
$username, $password);
$this->connection->setAttribute(PDO::ATTR_ERRMODE,
PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
$this->connection = null;
die($e->getMessage());
}
}
}
Or I've even seen people use a __construct then a seperate connect function
So what exactly is the difference? Is there a performance benefit by doing it a particular way? Or is there a way that is more correct than the other or are all three if these incorrect ways of doing it? I haven't found a reliable source to find an answer.
For the most cases 3rd example is the best:
In fact, PDO is already a database class. So, if you have no particular reason to create another on top of it, PDO itelf is just a perfect:
$pdo = new PDO('mysql:host=localhost;dbname=dbname', $username,$password);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
is all you actually need.
There are no noticeable performance differences between the two.
The second way is preferred by a lot of people because a database object would be kind of useless if it didn't try to connect to a database. Because attempting to connect to a database is so vital to the object's worth / existence, it makes sense to send in the connection details via the constructor so that it can attempt a connection as soon as it is being instantiated. Thus, changing:
$obj = new myClass();
$obj->username = "root";
$obj->password = "password";
$pdo = $obj->connect();
to
$obj = new myClass('localhost', 'root', 'mypassword');
I have, what I think/hope, is a very simple PHP question. I have made a class to create database connections and issue common queries. I am trying to open two different database connections by creating two objects from the same database class. My code is as follows:
//connect to DB
$dbh = new DB('localhost', 'db1', 'user', 'pass');
//check connection
if(!$dbh->getStatus()) {
echo($dbh->getErrorMsg());
die;
}//if
//connect to DB 2
$dbh2 = new DB('localhost', 'db2', 'user', 'pass');
//check connection
if(!$dbh2->getStatus()) {
echo($dbh2->getErrorMsg());
die;
}//if
However, when I call a method for $dbh to query the database, it attempts to query with the credentials for $dbh2.
My DB constructor is below:
class DB {
function __construct($host, $db, $user, $pass) {
$dbh = mysql_connect($host, $user, $pass);
mysql_select_db($db, $dbh);
if(!$dbh) {
$this->status = false;
$this->error_msg = 'Error connecting to database: '.mysql_error();
return(false);
}//if
$this->dbh = $dbh;
$this->resetStatusAndErrors();
return($dbh);
}//_construct
Simple solution: Use PDO instead. It does exactly what you want, probably has better syntax and implementation and abstracts the interface for DB access.
You're not showing the full class, but the most probable reason is that you are not passing the current connection to the mysql_query() command.
Save $dbh as a property of your class, and add the connection parameter to each mysql_ function that accepts it:
mysql_query("SELECT * from.......", $this->dbh);
That said, if you are building this from scratch at the moment, take a look whether you don't want to use PDO instead. It is better, safer and more flexible than the old style mySQL library.
If you are using the mysql extension (using either mysqli or PDO_MySQL would give both superior performance, more features, etc., so check that for new code), you'll have to store the database handle, and use that on every mysql_* call:
class db {
....
function query($query){
return mysql_query($query, $this->dbh);//notice the second parameter.
}
}