Connection differences between different database management systems in PHP

Differences in connection between different DBMS in PHP: MySQL: Using the mysqli extension, host name, user name, and password are required. PostgreSQL: Using the PDO extension, use the pgsql clause to specify the hostname, port, and database name. MongoDB: Use the MongoDB client library, specifying the hostname and port. By understanding these differences, developers can establish reliable database connections based on their specific DBMS.

Connection differences between different database management systems in PHP

PHP is a powerful server-side programming language. Allows developers to connect to various database management systems (DBMS) to store and retrieve data. Although the basic steps of the join process are generally similar, there are some key differences depending on the specific DBMS being used.

Connect to MySQL

<?php
$servername = "localhost";
$username = "username";
$password = "password";

// 创建一个 MySQL 连接
$conn = new mysqli($servername, $username, $password);

// 检查连接
if ($conn->connect_error) {
    die("连接失败：" . $conn->connect_error);
}
?>

Connect to PostgreSQL

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建一个 PostgreSQL 连接
$conn = new PDO("pgsql:host=$servername;port=5432;dbname=$dbname", $username, $password);

// 检查连接
if (!$conn) {
    die("连接失败：" . pg_last_error());
}
?>

Connect to MongoDB

<?php
$servername = "localhost";
$port = 27017;
$dbname = "database_name";

// 创建一个 MongoDB 连接
$client = new MongoDB\Client("mongodb://localhost:27017");

// 选择数据库
$db = $client->selectDatabase($dbname);
?>

Practical case: Retrieving data using MySQL

<?php
// 创建一个 MySQL 连接
$conn = new mysqli($servername, $username, $password);

// 准备一个 SQL 查询
$sql = "SELECT * FROM employees";

// 执行查询
$result = $conn->query($sql);

// 如果查询成功，则遍历结果
if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "员工姓名： " . $row["first_name"] . " " . $row["last_name"] . "<br>";
    }
} else {
    echo "没有记录找到";
}
?>

By understanding the connection differences of different DBMS, developers can establish reliable and efficient database connections in PHP to access, store and manipulate data .

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