Dev

queries/createIndexes.sql

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+
+
+
+	use RestaurantReservation ;
+
+-- 1. ReservationId in Orders table
+CREATE INDEX idx_orders_reservationid ON Orders(ReservationId);
+
+-- 2. RestaurantId in Reservations table
+CREATE INDEX idx_reservations_restaurantid ON Reservations(RestaurantId);
+
+-- 3. OrderId in OrderItems table
+CREATE INDEX idx_orderitems_orderid ON OrderItems(OrderId);
+
+-- 4. ItemId in OrderItems table
+CREATE INDEX idx_orderitems_itemid ON OrderItems(ItemId);
+
+-- 5. EmployeeId in Orders table
+CREATE INDEX idx_orders_employeeid ON Orders(EmployeeId);
+
+-- 6. ReservationDate in Reservations table
+CREATE INDEX idx_reservations_reservationdate ON Reservations(ReservationDate);

queries/fn_CalculateEmployeeSalary.sql

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+
+ --  **Database Function - Calculate Employees Salary**:
+  -- **Function Name**: **`fn_CalculateEmployeeSalary`**
+  -- **Purpose**: Compute the salary for a given employee.
+  -- **Parameter**: `EmployeeId`
+  -- **Implementation**: Salary is defined as: # number of orders made by specific employee * employee rank.
+  -- Employee�s rank based on position: Position = `VIPOrdersWaiter` = 5, `StandardWaiter` = 4, `AssistantWaiter`  = 3.
+  -- **Return**: salary for the `EmployeeId`.
+
+CREATE FUNCTION fn_CalculateEmployeeSalary(@EmployeeId INT)
+RETURNS INT as
+begin 
+DECLARE @cnt INT=(select count(*) from Orders where EmployeeId=@EmployeeId);
+DECLARE @pos NVARCHAR(100) = (SELECT Position FROM Employees WHERE EmployeeId = @EmployeeId);
+DECLARE @rank INT = CASE 
+        WHEN @pos = 'VIPOrdersWaiter' THEN 5
+        WHEN @pos = 'StandardWaiter' THEN 4
+        WHEN @pos = 'AssistantWaiter' THEN 3
+        ELSE 2 END;
+    RETURN ISNULL(@cnt,0) * @rank;
+end;
+ SELECT dbo.fn_CalculateEmployeeSalary(2) AS SalaryForEmployee2;
+
+
+

queries/fn_CalculateRevenue.sql

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+
+ -- **Database Function - Calculate Restaurant Revenue**: 
+ --   - **Function Name**: **`fn_CalculateRevenue`**
+ --   - **Purpose**: Compute revenue made by a specific restaurant.
+ --   - **Parameter**: `RestaurantId`
+ --   - **Return**: total revenue amount for the `RestaurantId` .
+
+create function fn_CalculateRevenue(@RestaurantId INT)
+RETURNS DECIMAL(18,2) as
+begin 
+return(
+select ISNULL(SUM(O.TotalAmount),0)
+      from Orders O
+	  JOIN Reservations r ON o.ReservationId = r.ReservationId
+        WHERE r.RestaurantId = @RestaurantId
+    );
+end;
+
+SELECT dbo.fn_CalculateRevenue(3) AS RevenueForRestaurant1;

queries/helperFun.sql

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+
+ --  13. **Stored Procedure - Borrowed Books Report**:
+    -- **Procedure Name**: **`sp_ResrvedTablesReport`**
+    -- **Purpose**: Generate a report of tables reserved within a specified date range.
+    -- **Parameters**: **`StartDate`**, **`EndDate`**
+    -- **Implementation**: Retrieve all tables reserved within the given range, with details like reservation date, party size and restaurant details.
+    -- **Return**: Tabulated report of reserved tables
+
+	-- GET NEW ID FOR INSERT NEW ORDER
+CREATE FUNCTION dbo.fn_GetNextOrderId()
+RETURNS INT
+AS
+BEGIN
+    DECLARE @NextId INT;
+
+    SELECT @NextId = ISNULL(MAX(OrderId), 0) + 1
+    FROM Orders;
+
+    RETURN @NextId;
+END;

queries/q01_list_reservations_for_customer.sql

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+
+use RestaurantReservation ;
+-- List all reservations for a specific customer
+
+DECLARE @CustomerId INT = 1;
+SELECT *
+FROM Reservations
+WHERE CustomerId=@CustomerId;

queries/q02_list_managers.sql

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+
+use RestaurantReservation ;
+-- List of Managers: Retrieve all employees holding Manager position. 
+
+SELECT *
+FROM Employees
+WHERE Position = 'Manager';

queries/q03_orders_and_menuitems_for_reservation.sql

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+
+use RestaurantReservation ;
+--List of Orders and Menu Items: Lists the orders placed on a specific given reservation along with the associated menu items.
+
+DECLARE @ReservationId INT = 1;
+SELECT *
+FROM Orders O
+JOIN OrderItems OI
+ON O.OrderId=OI.OrderId
+JOIN MenuItems MI
+ON MI.ItemId=OI.ItemId
+WHERE O.ReservationId = @ReservationId;
+

queries/q04_ordered_menuitems_for_reservation.sql

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+
+use RestaurantReservation ;
+--List of Ordered Menu Items: Lists the menu items ordered by a specific reservation.
+
+DECLARE @ReservationId INT = 1;
+SELECT MI.*
+FROM Orders O
+JOIN OrderItems OI
+ON O.OrderId = OI.OrderId
+JOIN MenuItems MI
+ON OI.ItemId = MI.ItemId
+WHERE o.ReservationId = @ReservationId;
+

queries/q05_avg_order_amount_by_employee.sql

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+
+use RestaurantReservation ;
+--Calculate Average Order Amount: Calculate the average order amount made through a specific employee.
+
+DECLARE @EmployeeId INT =7;
+
+SELECT emp.EmployeeId,emp.FirstName,emp.LastName, AVG(TotalAmount) AS AvgAmount
+FROM Orders o
+join Employees emp
+on o.EmployeeId=emp.EmployeeId
+WHERE o.EmployeeId = @EmployeeId
+group by emp.EmployeeId,emp.FirstName,emp.LastName;

queries/q08_reservations_with_2plus_orders_cte.sql

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+
+--Reservation�s Order with CTEs: Identify reservations which have 2 or more orders using CTEs.
+
+
+WITH OrdersPerReservation AS (
+    SELECT ReservationId, COUNT(*) AS OrdersCount
+    FROM Orders
+    WHERE ReservationId IS NOT NULL
+    GROUP BY ReservationId
+)
+SELECT *
+FROM Reservations R
+JOIN OrdersPerReservation OPR
+ON R.ReservationId=OPR.ReservationId
+WHERE OPR.OrdersCount>=2;

queries/q09_restaurant_popularity.sql

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+
+--Restaurant Popularity using Aggregation: Rank restaurants by the reservation frequency.
+
+
+
+SELECT r.RestaurantId, r.Name,
+       COUNT(res.ReservationId) AS ReservationCount
+FROM Restaurants r
+LEFT JOIN Reservations res ON r.RestaurantId = res.RestaurantId
+GROUP BY r.RestaurantId, r.Name
+ORDER BY ReservationCount DESC;

queries/q10_popular_menu_item_per_restaurant_month.sql

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+
+--Popular Menu Item Analysis using Joins and Window Functions: Identify the most popular menu item for each restaurant for a given month.
+DECLARE @Year INT = 2025;
+DECLARE @Month INT = 5;
+
+
+;WITH ItemsInMonth AS (
+    SELECT mi.RestaurantId, mi.ItemId, mi.Name,
+           SUM(oi.Quantity) AS QtySold
+    FROM OrderItems oi
+    JOIN Orders o ON oi.OrderId = o.OrderId
+    JOIN MenuItems mi ON oi.ItemId = mi.ItemId
+    WHERE YEAR(o.OrderDate) = @Year AND MONTH(o.OrderDate) = @Month
+    GROUP BY mi.RestaurantId, mi.ItemId, mi.Name
+),Ranked AS (
+    SELECT RestaurantId, ItemId, Name, QtySold,
+           ROW_NUMBER() OVER (PARTITION BY RestaurantId ORDER BY QtySold DESC) AS rn
+    FROM ItemsInMonth
+)SELECT RestaurantId, ItemId, Name, QtySold
+FROM Ranked
+WHERE rn = 1
+ORDER BY RestaurantId;

queries/sp_AddNewOrder.sql

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+
+
+
+	-- **Stored Procedure - Add New Order**:
+    -- **Procedure Name**: **`sp_AddNewOrder`**
+    -- **Purpose**: Streamline the process of adding a new order.
+    -- **Parameters**: **`ReservationId`**, **`EmployeeId`**, **`OrderDate`**, and **`TotalAmount`**.
+    -- **Implementation**: Check if the specified reservation and employee exist, if not, return an error message, if existing, add new order.
+    -- **Return**: The new **`OrderId`** or an error message.
+
+IF OBJECT_ID('dbo.sp_AddNewOrder','P') IS NOT NULL
+    DROP PROCEDURE dbo.sp_AddNewOrder;
+GO
+
+CREATE PROCEDURE dbo.sp_AddNewOrder
+    @ReservationId INT,
+    @EmployeeId INT,
+    @OrderDate DATETIME,
+    @TotalAmount DECIMAL(12,2)
+AS
+BEGIN
+    SET NOCOUNT ON;
+
+
+    IF NOT EXISTS (SELECT 1 FROM Reservations WHERE ReservationId = @ReservationId)
+    BEGIN
+        RAISERROR('Reservation not found (ReservationId=%d).',16,1,@ReservationId);
+        RETURN -1;
+    END
+
+
+    IF NOT EXISTS (SELECT 1 FROM Employees WHERE EmployeeId = @EmployeeId)
+    BEGIN
+        RAISERROR('Employee not found (EmployeeId=%d).',16,1,@EmployeeId);
+        RETURN -2;
+    END
+
+
+    DELETE FROM Orders
+    WHERE ReservationId = @ReservationId;
+
+
+    INSERT INTO Orders (OrderId, ReservationId, EmployeeId, OrderDate, TotalAmount)
+    VALUES (dbo.fn_GetNextOrderId(), @ReservationId, @EmployeeId, @OrderDate, @TotalAmount);
+
+
+    SELECT MAX(OrderId) AS NewOrderId FROM Orders;
+END;
+GO
+
+
+EXEC dbo.sp_AddNewOrder 
+    @ReservationId = 1, 
+    @EmployeeId = 2000, 
+    @OrderDate = '2025-09-29 14:35',  
+    @TotalAmount = 50.00;
+
+SELECT MAX(OrderId) AS NewOrderId FROM Orders;
+select * from Orders;

queries/sp_FutureReservedTables.sql

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+
+
+ --15. **SQL Stored Procedure with Temp Table**:
+     -- Design a stored procedure that retrieves all tables which have future reservations.
+	--  Store these tables in a temporary table, then join this temp table with the **`Restaurants`**
+	-- table to list out the specific information about the associated restaurants.
+	use RestaurantReservation ;
+
+CREATE PROCEDURE dbo.sp_FutureReservedTables
+AS
+BEGIN
+    SET NOCOUNT ON;
+
+
+    IF OBJECT_ID('tempdb..#FutureTables') IS NOT NULL
+        DROP TABLE #FutureTables;
+
+
+    SELECT DISTINCT
+        t.TableId,
+        t.RestaurantId,
+        t.Capacity
+    INTO #FutureTables
+    FROM Tables t
+    JOIN Reservations r ON t.TableId = r.TableId
+    WHERE r.ReservationDate > GETDATE();
+
+
+    SELECT
+        ft.TableId,
+        ft.RestaurantId,
+        ft.Capacity,
+        res.Name      AS RestaurantName,
+        res.Address   AS RestaurantAddress,
+        res.PhoneNumber AS RestaurantPhone
+    FROM #FutureTables ft
+    LEFT JOIN Restaurants res ON ft.RestaurantId = res.RestaurantId
+    ORDER BY res.Name, ft.TableId;
+
+END;
+
+EXEC dbo.sp_FutureReservedTables;

queries/sp_ResrvedTablesReport.sql

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+
+ --  13. **Stored Procedure - Borrowed Books Report**:
+    -- **Procedure Name**: **`sp_ResrvedTablesReport`**
+    -- **Purpose**: Generate a report of tables reserved within a specified date range.
+    -- **Parameters**: **`StartDate`**, **`EndDate`**
+    -- **Implementation**: Retrieve all tables reserved within the given range, with details like reservation date, party size and restaurant details.
+    -- **Return**: Tabulated report of reserved tables
+
+CREATE PROCEDURE sp_ResrvedTablesReport
+    @StartDate DATETIME,
+    @EndDate DATETIME
+AS 
+begin 
+ SELECT r.ReservationId, r.ReservationDate, r.PartySize,
+           rest.RestaurantId, rest.Name AS RestaurantName, rest.Address, rest.PhoneNumber,
+           r.TableId,   
+           r.CustomerId 
+    FROM Reservations r
+    JOIN Restaurants rest ON r.RestaurantId = rest.RestaurantId
+    WHERE r.ReservationDate BETWEEN @StartDate AND @EndDate
+
+end;
+EXEC dbo.sp_ResrvedTablesReport '2025-01-01','2025-02-28';
+
+

queries/trg_LogReservationAudit.sql

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+
+
+ --16. **Trigger Implementation**
+   --  Design a trigger to log an entry into a separate **`AuditLog`** table whenever a table get reserved.
+	--The **`AuditLog`** should capture `ResturantId`, `TableId`, `ReservationDate` and **`ChangeDate`**.
+
+	use RestaurantReservation ;
+
+CREATE TABLE dbo.AuditLog (
+    AuditId INT IDENTITY(1,1) PRIMARY KEY,
+    RestaurantId INT,
+    TableId INT,
+    ReservationDate DATETIME,
+    ChangeDate DATETIME DEFAULT GETDATE() 
+);
+
+CREATE TRIGGER dbo.trg_LogReservation
+ON dbo.Reservations
+AFTER INSERT
+AS
+BEGIN
+    INSERT INTO dbo.AuditLog (RestaurantId, TableId, ReservationDate)
+    SELECT RestaurantId, TableId, ReservationDate
+    FROM inserted;
+END;

queries/vw_EmployeesFull.sql

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+
+--Retrieve Employees details with Views: Use a view to list all employees information including their restaurants details
+
+
+CREATE VIEW EmployeesFull
+AS
+SELECT e.EmployeeId, e.FirstName, e.LastName, e.Position, e.RestaurantId,
+       r.Name AS RestaurantName, r.Address AS RestaurantAddress, r.PhoneNumber AS RestaurantPhone
+FROM Employees e
+JOIN Restaurants r ON e.RestaurantId = r.RestaurantId;
+
+SELECT * FROM EmployeesFull;

queries/vw_ReservationsFull.sql

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+
+--Retrieve Reservations Report with Views: Use a view to list all reservations information including restaurants and customers information.
+
+
+CREATE VIEW ReservationsReport AS
+   SELECT r.ReservationId, r.ReservationDate, r.PartySize, r.TableId,
+       c.CustomerId, c.FirstName AS CustomerFirstName, c.LastName AS CustomerLastName, c.Email, c.PhoneNumber AS CustomerPhone,
+       res.RestaurantId, res.Name AS RestaurantName, res.Address AS RestaurantAddress, res.PhoneNumber AS RestaurantPhone
+
+FROM Reservations r
+JOIN Customers c ON r.CustomerId = c.CustomerId
+JOIN Restaurants res ON r.RestaurantId = res.RestaurantId;
+
+SELECT * FROM ReservationsReport;