How can the use of INDEX, UNIQUE, and PRIMARY keys in PHP MySQL databases affect the generation of customer numbers?

Using INDEX, UNIQUE, and PRIMARY keys in PHP MySQL databases can affect the generation of customer numbers by ensuring that each customer has a unique identifier. By setting a PRIMARY key on the customer table, we can guarantee that each customer has a unique number assigned automatically by the database. Additionally, using UNIQUE keys can prevent duplicate customer numbers from being generated.

// Create a table with a PRIMARY key on the customer_id column
$sql = "CREATE TABLE customers (
    customer_id INT AUTO_INCREMENT PRIMARY KEY,
    customer_name VARCHAR(50) NOT NULL,
    email VARCHAR(50) UNIQUE
)";