Question

我将在SQL Server 2014中创建数据库，但我遇到了问题。

需要使用此选项：当用户想要注册时，选择国家/地区，城市显示并选择它。

例如：当用户选择美国，显示（NewYourk，华盛顿，...）

CREATE TABLE orders
(
    OrderID INT IDENTITY (1,1) NOT NULL PRIMARY KEY,
    Fname VARCHAR(50) NOT NULL,
    Lname VARCHAR(50) NOT NULL,
    Tel VARCHAR(15),
    Counts INT NOT NULL, 
    DaysID INT NOT NULL,
    CountryID INT NOT NULL,
    CityID INT NOT NULL,
    Address VARCHAR(1024) NOT NULL,
    FOREIGN KEY (DaysID) REFERENCES WeekDays(DaysID),
    FOREIGN KEY (CountryID) REFERENCES Country(ContryID),
    FOREIGN KEY (CityID) REFERENCES City(CityID)
)
GO
CREATE TABLE WeekDays
(
    DaysID INT IDENTITY (10000001,1) NOT NULL PRIMARY KEY,
    DaysName VARCHAR(50) NOT NULL
)
GO
CREATE TABLE Country
(
    CountryID INT IDENTITY (2000000,1) NOT NULL PRIMARY KEY,
    CountryName VARCHAR(100)
)
CREATE TABLE City
(
    CityID INT IDENTITY (2000000,1) NOT NULL PRIMARY KEY,
    CityName VARCHAR(100)
)

Answer 1

为此你必须在City表中有一个CountryID的FOREIGN KEY，以便你可以获取美国的城市

CREATE TABLE City
(
    CityID INT IDENTITY (2000000,1) NOT NULL PRIMARY KEY,
    CityName VARCHAR(100)
    CountryID INT 
    FOREIGN KEY (CountryID ) REFERENCES Country(CountryID )
)

--FETCH RECORDS

SELECT * FORM City
WHERE CountryID=1 -- OR whatever the id of the Country

需要帮助才能创建数据库？

1 个答案: