What debugging techniques can be used to troubleshoot PHP PDOExceptions related to duplicate entry errors in a database?

When encountering PDOExceptions related to duplicate entry errors in a database, one common debugging technique is to catch the exception and then analyze the error message to determine which field or key is causing the duplication. This information can help identify the root cause of the issue, such as a unique constraint violation or a primary key conflict. Once the problematic field or key is identified, appropriate actions can be taken to prevent or handle duplicate entries in the database.

try {
    // Your PDO database connection and query here
} catch (PDOException $e) {
    if ($e->errorInfo[1] == 1062) {
        // Handle duplicate entry error
        echo "Duplicate entry error: " . $e->getMessage();
    } else {
        // Handle other types of PDOExceptions
        echo "PDO error: " . $e->getMessage();
    }
}