What are the potential pitfalls of not checking for duplicate entries before inserting data into a database using PHP?

Potential pitfalls of not checking for duplicate entries before inserting data into a database using PHP include: 1. Data integrity issues: Duplicate entries can lead to inconsistencies and errors in the database. 2. Performance degradation: Inserting duplicate data can slow down database operations. 3. Unwanted data redundancy: Duplicate entries can clutter the database and make it harder to manage. To prevent these issues, you can check for duplicates before inserting data by querying the database to see if the entry already exists.

// Check for duplicate entry before inserting data
$existing_entry = $pdo->prepare("SELECT * FROM table_name WHERE column_name = :value");
$existing_entry->bindParam(':value', $value_to_check);
$existing_entry->execute();

if($existing_entry->rowCount() == 0) {
    // Insert data into the database
    $insert_data = $pdo->prepare("INSERT INTO table_name (column_name) VALUES (:value)");
    $insert_data->bindParam(':value', $value_to_insert);
    $insert_data->execute();
    echo "Data inserted successfully.";
} else {
    echo "Duplicate entry found.";
}