What are the commonly used databases in PHPCMS?

PHPCMS is a commonly used open source content management system, which often involves database operations during the development process. In the process of using PHPCMS, commonly used databases include MySQL, Mysqli and PDO. These commonly used databases will be introduced in detail below, with specific code examples attached.

1. MySQL database operation

MySQL is one of the most popular relational databases currently and supports SQL language operations. In PHPCMS, operations using the MySQL database require connecting to the database first, and then executing SQL statements to perform operations such as additions, deletions, modifications, and queries. The following is a simple MySQL database connection example:

// 连接MySQL数据库
$servername = "localhost";
$username = "root";
$password = "root";
$dbname = "mydatabase";

$conn = new mysqli($servername, $username, $password, $dbname);

// 检测连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}
echo "连接成功";

You can then perform SQL queries and other operations, such as:

// 查询数据
$sql = "SELECT id, name, email FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()){
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. " " . $row["email"]. "<br>";
    }
} else {
    echo "0 结果";
}

2. Mysqli database operation

Mysqli It is an improved version of MySQL database and provides two operation modes: object-oriented and procedural. Using Mysqli to operate the database also requires first connecting to the database and executing SQL statements. The following is an example of a Mysqli connection:

// 连接Mysqli数据库
$servername = "localhost";
$username = "root";
$password = "root";
$dbname = "mydatabase";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检测连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}
echo "连接成功";

Examples of operations such as executing SQL queries:

// 查询数据
$sql = "SELECT id, name, email FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()){
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. " " . $row["email"]. "<br>";
    }
} else {
    echo "0 结果";
}

3. PDO database operation

PDO is a database operation extension provided by PHP , supports a variety of databases, and uses PDO to effectively avoid SQL injection attacks. The methods of connecting to the database and executing SQL statements are similar to the above two methods. The following is a simple PDO connection and query example:

// 连接PDO数据库
$servername = "localhost";
$username = "root";
$password = "root";
$dbname = "mydatabase";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // 设置 PDO 错误模式为异常
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "连接成功"; 
}
catch(PDOException $e){
    echo "连接失败: " . $e->getMessage();
}

// 查询数据
$stmt = $conn->prepare("SELECT id, name, email FROM users"); 
$stmt->execute();

$result = $stmt->fetchAll();
if(count($result) > 0){
    foreach($result as $row){
        echo "id: " . $row['id'] . " - Name: " . $row['name'] . " " . $row['email'] . "<br>";
    }
}
else {
    echo "0 结果";
}

The above are examples of commonly used database operation codes in PHPCMS. The specific database selection depends on the needs of the project and the development environment. Developers need to choose the appropriate one according to the specific situation. How the database operates.

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