在sql中插入選擇題和答案

Question

我有兩個表，分別爲Questions和Answers，它們分別存儲多選題和4個可能的答案。我試圖一次插入一個問題及其4個答案。

The INSERT statement conflicted with the FOREIGN KEY constraint .... "dbo.Answers", column 'AnswerID'. 

The INSERT statement conflicted with the FOREIGN KEY constraint table "dbo.Questions", column 'QuestionID'. 

這裏是我的表是這樣的：

CREATE TABLE [dbo].[Questions] ( 
    [QuestionID] INT   IDENTITY (1, 1) NOT NULL PRIMARY KEY, 
    [HistID]  INT   NOT NULL, 
    [Question] NCHAR (300) NOT NULL, 
    [AnswerID] CHAR   NOT NULL, 
    FOREIGN KEY (AnswerID) REFERENCES [dbo].Answers (AnswerID), 
    FOREIGN KEY (HistID) REFERENCES [dbo].HistoricalEvents (HistID) 
); 

CREATE TABLE [dbo].[Answers] (
    [QuestionID] INT   NOT NULL, 
    [AnswerID] CHAR  NOT NULL, 
    [Choice]  NCHAR (200) NOT NULL, 
    FOREIGN KEY (QuestionID) REFERENCES [dbo].[Questions] (QuestionID), 
    PRIMARY KEY ([AnswerID]) 
); 

這些都是刀片我想：

INSERT INTO Questions (HistID, Question, AnswerID) 
VALUES (
2, 
'A major cause of the growth of state and Federal highway systems after World War II was the ___', 
'C' 
) 

Declare @QuestionID INT = SCOPE_IDENTITY() 


INSERT INTO Answers(QuestionID, AnswerID, Choice) 
VALUES 
(
@QuestionID, 
'A', 
'increased use of mass transit systems' 
), 

(
@QuestionID, 
'B', 
'growing prosperity of inner-city areas' 
), 

(
@QuestionID, 
'C', 
'rapid development of suburbs' 
), 

(
@QuestionID, 
'D', 
'return of city dwellers to farm areas' 
) 

預期輸出： 我想上面的命令（或者它應該改變成什麼）來對這些表進行以下更改：

Questions: 
QuestionID HistID Question     AnswerID 
-------------------------------------------------------- 
    1   2  "A major cause of the... C  

Answers: 
QuestionID AnswerID Choice 
-------------------------------- 
    1   A   increased use of mass transit systems 
    1   B   growing prosperity of inner-city areas 
    1   C   rapid development of suburbs 
    1   D   return of city dwellers to farm areas 

Answer 1

您已完成所謂的循環引用。您在Answers表中將Answers設置爲FK，將Question設置爲FK。在這裏你已經在兩個桌子上放置了限制。所以你不能插入，因爲插入過程中沒有兩個存在。

這應該是：

問題--->答案[QuestionId] FK僅

這裏有一個提示，糾正你的模式：

問表 -

+------------+ 
| QuestionId | (PK, int) 
+------------+ 
| HistID  | (FK, int) 
+------------+ 
| Question | 
+------------+ 

AnswerTable（可供選擇） -

+------------+ 
| AnswerId | (PK, int) 
+------------+ 
| Choice  | (char) -- A, B, C, D etc. 
+------------+ 
| Answer  | (nvarchar(100)) -- limit depends on your choice 
+------------+ 
| QuestionId | (FK, int) -- 1 to many relationship means 1 question can have multiple answers choice. 
+------------+ 

正確答案（選擇）映射表（FK都將是複合鍵） -

+------------+ 
| AnswerId | (FK, int) 
+------------+   |--- composite primary key, 1-1 relationship means 1 question have only one correct choice. 
| QuestionId | (FK, int) 
+------------+ 

見 - SQL FIDDLE DEMO顯示在執行的想法。