Câu 3

CREATE TABLE Customer (
    CustomerID INT PRIMARY KEY,
    CustomerName NVARCHAR(100),
    Address NVARCHAR(255),
    Phone NVARCHAR(20),
    Email NVARCHAR(100)
);

CREATE TABLE Employee (
    EmployeeID INT PRIMARY KEY,
    EmployeeName NVARCHAR(100),
    Position NVARCHAR(50),
    Salary DECIMAL(10,2),
    HireDate DATE
);

CREATE TABLE Product (
    ProductID INT PRIMARY KEY,
    ProductName NVARCHAR(100),
    Price DECIMAL(10,2),
    Stock INT,
    Description NVARCHAR(255)
);

CREATE TABLE [Order] (
    OrderID INT PRIMARY KEY,
    OrderDate DATE,
    TotalAmount DECIMAL(10,2),
    CustomerID INT,
    EmployeeID INT,
    FOREIGN KEY (CustomerID) REFERENCES Customer(CustomerID),
    FOREIGN KEY (EmployeeID) REFERENCES Employee(EmployeeID)
);

CREATE TABLE OrderDetail (
    OrderID INT,
    ProductID INT,
    Quantity INT,
    UnitPrice DECIMAL(10,2),
    Total DECIMAL(10,2),
    PRIMARY KEY (OrderID, ProductID),
    FOREIGN KEY (OrderID) REFERENCES [Order](OrderID),
    FOREIGN KEY (ProductID) REFERENCES Product(ProductID)
);