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🔄 SQL में Column Name कैसे बदलें? (Best Explanation)

SQL Server में किसी भी टेबल के column name को rename करने के लिए हम sp_rename command का इस्तेमाल करते हैं।

अगर आपकी टेबल का नाम fcm_tokens है और आप पुराने column visitor_id को बदलकर user_id रखना चाहते हैं, तो SQL में ये query लिखें:

EXEC sp_rename 'fcm_tokens.visitor_id', 'user_id', 'COLUMN';

✔ यह Query क्या करती है?

fcm_tokens → आपकी table का नाम

visitor_id → पुराना column name

user_id → नया column name

COLUMN → SQL Server को बताता है कि आप एक column को rename कर रहे हैं

📌 Important Note:

Column rename करने से data delete नहीं होता, सिर्फ नाम बदलता है। इसलिए यह command safe है।

3 weeks ago | [YT] | 0

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What does the method calculateTotal() return?

4 weeks ago | [YT] | 0

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What will happen if product.isAvailable(quantity) returns false in the Order class?

4 weeks ago | [YT] | 0

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Which method is responsible for reducing the number of items in stock?

4 weeks ago | [YT] | 0

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What does the method isAvailable(int quantity) most likely return?

4 weeks ago | [YT] | 0

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Which OOP concept is used when a Product class contains attributes like name, price, and stock?

4 weeks ago | [YT] | 0

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Full Code
📌 Java Code Example – Online Shopping Order Processing:-

// Real-life example: Online Shopping Order

class Product {
String name;
double price;
int stock;

Product(String name, double price, int stock) {
this.name = name;
this.price = price;
this.stock = stock;
}

boolean isAvailable(int quantity) {
return stock >= quantity;
}

void reduceStock(int quantity) {
stock -= quantity;
}
}

class Order {
Product product;
int quantity;

Order(Product product, int quantity) {
this.product = product;
this.quantity = quantity;
}

double calculateTotal() {
return product.price * quantity;
}

void placeOrder() {
if (product.isAvailable(quantity)) {
product.reduceStock(quantity);
System.out.println("Order placed successfully!");
System.out.println("Product: " + product.name);
System.out.println("Quantity: " + quantity);
System.out.println("Total Amount: ₹" + calculateTotal());
} else {
System.out.println("Sorry! Not enough stock for " + product.name);
}
}
}

public class EcommerceApp {
public static void main(String[] args) {
Product laptop = new Product("Dell Laptop", 55000, 5);

// User places an order for 2 laptops
Order order1 = new Order(laptop, 2);
order1.placeOrder();

// Another user places an order for 4 laptops (not enough stock!)
Order order2 = new Order(laptop, 4);
order2.placeOrder();
}
}

4 weeks ago | [YT] | 0

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Can Generics be used with enums?

1 month ago | [YT] | 0

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Can we have static members in a generic class?

1 month ago | [YT] | 0

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Can we use multiple bounds in Generics

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