What are the best practices for preventing duplicate entries in a database using PHP?

To prevent duplicate entries in a database using PHP, you can utilize the `INSERT IGNORE` or `ON DUPLICATE KEY UPDATE` MySQL queries. By setting a unique constraint on the database table, you can ensure that duplicate entries are not allowed. Additionally, you can check for existing entries before inserting new data to avoid duplicates. 

// Connect to the database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";
$conn = new mysqli($servername, $username, $password, $dbname);

// Check for existing entry before inserting
$check_query = "SELECT * FROM table_name WHERE column_name = 'value'";
$result = $conn->query($check_query);

if ($result->num_rows == 0) {
    // Insert new entry if it does not already exist
    $insert_query = "INSERT INTO table_name (column_name) VALUES ('value')";
    $conn->query($insert_query);
} else {
    echo "Entry already exists";
}

// Close the database connection
$conn->close();

Keywords

database PHP duplicate entries prevention validation

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