What are the best practices for storing and handling special characters like entities in a PHP application, particularly when interacting with a database?

Special characters like entities can cause issues when storing or retrieving data from a database in a PHP application. To handle special characters properly, it's important to sanitize input data before storing it in the database and escape output data before displaying it to the user. This helps prevent SQL injection attacks and ensures that special characters are handled correctly. 

// Sanitize input data before storing in the database
$inputData = $_POST['input_data'];
$sanitizedData = mysqli_real_escape_string($connection, $inputData);

// Store the sanitized data in the database
$query = "INSERT INTO table_name (column_name) VALUES ('$sanitizedData')";
mysqli_query($connection, $query);

// Escape output data before displaying to the user
$query = "SELECT * FROM table_name";
$result = mysqli_query($connection, $query);

while ($row = mysqli_fetch_assoc($result)) {
    $outputData = htmlentities($row['column_name']);
    echo $outputData;
}

Keywords

UTF-8 htmlentities htmlspecialchars mysqli_real_escape_string prepared statements

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