PHP Connect to MySQL
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PHP Connect to MySQL
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PHP 5 and later can work with a MySQL database using:
MySQLi extension (the "i" stands for improved)- PDO (PHP Data Objects)
Earlier versions of PHP used the MySQL extension. However, this
extension was deprecated in 2012.
Should I Use MySQLi or PDO?
If you need a short answer, it would be "Whatever you like".
Both MySQLi and PDO have their advantages:
PDO will work on 12 different database systems, whereas MySQLi will only
work with MySQL databases.
So, if you have to switch your project
to use another database, PDO makes the process easy. You only have
to change the connection string and a few queries. With MySQLi, you will need
to rewrite the entire code - queries included.
Both are object-oriented, but MySQLi also offers a procedural API.
Both support Prepared Statements. Prepared Statements protect
from SQL injection, and are very important for web application security.
MySQL Examples in Both MySQLi and PDO Syntax
In this, and in the following chapters we demonstrate three ways of working
with PHP and MySQL:
- MySQLi (object-oriented)
- MySQLi (procedural)
- PDO
MySQLi Installation
For Linux and Windows: The MySQLi extension is automatically installed in
most cases, when php5 mysql package is installed.
For installation details, go to:
http://php.net/manual/en/mysqli.installation.php
PDO Installation
For installation details, go to:
http://php.net/manual/en/pdo.installation.php
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Open a Connection to MySQL
Before we can access data in the MySQL database, we need to be able to connect to
the server:
Example (MySQLi Object-Oriented)
<?php
$servername = "localhost";
$username = "username";
$password = "password";
// Create connection
$conn = new mysqli($servername, $username, $password);
// Check connection
if ($conn->connect_error)
die("Connection failed: " . $conn->connect_error);
echo "Connected successfully";
?>
PHP is an amazing and popular language!
Note on the object-oriented example above: $connect_error was
broken until PHP 5.2.9 and 5.3.0. If you need to ensure compatibility with PHP
versions prior to 5.2.9 and 5.3.0, use the following code instead:
// Check connection
if (mysqli_connect_error())
die("Database connection failed: " . mysqli_connect_error());
Example (MySQLi Procedural)
<?php
$servername = "localhost";
$username = "username";
$password = "password";
// Create connection
$conn = mysqli_connect($servername, $username, $password);
// Check connection
if (!$conn)
die("Connection failed: " . mysqli_connect_error());
echo "Connected successfully";
?>
Example (PDO)
<?php
$servername = "localhost";
$username = "username";
$password = "password";
try
$conn = new PDO("mysql:host=$servername;dbname=myDB", $username, $password);
// set the PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "Connected successfully";
catch(PDOException $e)
echo "Connection failed: " . $e->getMessage();
?>
Notice that in the PDO example above we have also
specified a database (myDB). PDO require a valid database
to connect to. If no database is specified, an exception is thrown.
Tip: A great benefit of PDO is that it
has an exception class to handle any problems that may
occur in our database queries. If an exception is thrown within the try block,
the script stops executing and flows directly to the first catch() block.
Close the Connection
The connection will be closed automatically when the script ends. To close the
connection before, use the following:
Example (MySQLi Object-Oriented)
$conn->close();Example (MySQLi Procedural)
mysqli_close($conn);
Example (PDO)
$conn = null;
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