Complete guide to connecting to database using PHP PDO

PHP PDO is a powerful extension for connecting to databases. The installation steps include installing the PDO extension (if required) and setting the error handling mode. To connect to the database, you need to create a PDO object and specify the connection parameters. To query a database, prepare a query statement and execute it. To update the database, prepare an update statement, bind parameters and perform the update. A hands-on example demonstrates how to obtain a user from the database.

Complete Guide to Connecting to Databases Using PHP PDO

PHP PDO (PHP Data Objects) is used in PHP to interact with databases Powerful and flexible extensions. It provides an object-oriented way to connect, query and update databases.

Installing PDO

First, make sure your version of PHP supports PDO. Then, if you're using PHP 5.1 or higher, PDO is already built into it. For earlier versions, you need to install the PDO extension:

pecl install pdo

Connecting to the database

Connecting to the database using PDO requires the following steps:

1. Create a PDO object:

$dsn = 'mysql:host=localhost;dbname=database_name';
$user = 'username';
$password = 'password';

$pdo = new PDO($dsn, $user, $password);

where $dsn is the data source name, which specifies the database type, host name, database name and other connection parameters.

2. Set error handling mode:

$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

This will throw an exception when an error occurs, making debugging easier.

Query database

To query the database, you can use the following steps:

1. Prepare a query statement:

$stmt = $pdo->prepare("SELECT * FROM table_name");

2. Execute query:

$stmt->execute();

3. Get the result:

$results = $stmt->fetchAll(PDO::FETCH_ASSOC);

Update database

To To update the database, you can use the following steps:

1. Prepare an update statement:

$stmt = $pdo->prepare("UPDATE table_name SET column_name = :value WHERE id = :id");

2. Bind parameters:

$stmt->bindParam(':value', $value);
$stmt->bindParam(':id', $id);

3. Execute update:

$stmt->execute();

Practical case: Get the user in the database

$stmt = $pdo->prepare("SELECT * FROM users");
$stmt->execute();
$users = $stmt->fetchAll(PDO::FETCH_ASSOC);

foreach ($users as $user) {
    echo $user['username'] . "\n";
}

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