How can persistent storage, such as a database, be used to store and retrieve user-modifiable variables in PHP?

Persistent storage, such as a database, can be used to store and retrieve user-modifiable variables in PHP by creating a database table to store the variables, establishing a connection to the database, and using SQL queries to insert, update, and retrieve the variables as needed. 

// Establish connection to the database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

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

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// Insert or update user-modifiable variable
$variable_name = "example_var";
$variable_value = "example_value";

$sql = "INSERT INTO user_variables (name, value) VALUES ('$variable_name', '$variable_value') ON DUPLICATE KEY UPDATE value='$variable_value'";

if ($conn->query($sql) === TRUE) {
    echo "Variable stored successfully";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

// Retrieve user-modifiable variable
$sql = "SELECT value FROM user_variables WHERE name='$variable_name'";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "Variable value: " . $row["value"];
    }
} else {
    echo "Variable not found";
}

$conn->close();

Keywords

persistent storage database user-modifiable variables PHP retrieve

Related Questions