Explain @Transactional

Our application only support DEBIT card payment.

url

/api/v1/orders

Json

Correct Request Body

{
    "order": {
        "totalQuantity": 3,
        "totalPrice": "2000",
        "shoppingCartId": 2
    },
    "payment": {
        "type": "DEBIT",
        "cardName": "Chuwa America",
        "cardNumber": "666 6666 6666 6666",
        "expiryYear": 2027,
        "expiryMonth": 7,
        "cvc": 123
    }
}

Wrong Request body (Credit card)

{
    "order": {
        "totalQuantity": 3,
        "totalPrice": "2000",
        "shoppingCartId": 2
    },
    "payment": {
        "type": "CREDIT",
        "cardName": "Chuwa America",
        "cardNumber": "666 6666 6666 6666",
        "expiryYear": 2027,
        "expiryMonth": 7,
        "cvc": 123
    }
}

Test

In service layer,

• you can comment off @Transactional then try to send request with wrong request body.
• or add @Transactional back then try to send request with wrong request body. check the difference in the database, figure out @Transactional help us rollback when failing.

Questions

• What is @Transactional? what is its role?
• When do we use it?