Sql server 无法将值NULL插入到不允许为NULL的列中

我创建了如下两个表：

CREATE TABLE Seller_(
    ID_SELLER INT NOT NULL,
    PASS VARCHAR (8) NULL,
    FIO VARCHAR (30) NULL,
    ADRESS VARCHAR (30) NULL,
    PRIMARY KEY (ID_SELLER),
);

CREATE TABLE Zakaz_(
    ID_ZAKAZ INT NOT NULL,
    DATE_ DATE NULL,
    ID_SELLER INT NOT NULL FOREIGN KEY REFERENCES Seller_(ID_SELLER) 
    PRIMARY KEY (ID_ZAKAZ)
);

INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (111,'abcd1','Anton','derevnya universiady');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (112,'abcd2','Andrey','pushkina');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (113,'abcd3','Abdul','krasnaya pozitsiya');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (114,'abcd1','Alsu','derevnya universiady');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (115,'abcd2','Anna','pushkina');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (116,'abcd3','Azamat','krasnaya pozitsiya');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (117,'abcd2','Sergei','pushkina');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (118,'abcd1','Leysan','derevnya universiady');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (119,'abcd1','Katya','derevnya universiady');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (120,'abcd3','Anastasia','krasnaya pozitsiya');

INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (111,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (112,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (113,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (114,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (115,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (116,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (117,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (118,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (119,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (112,GETDATE());

我在这些表格中插入如下内容：

CREATE TABLE Seller_(
    ID_SELLER INT NOT NULL,
    PASS VARCHAR (8) NULL,
    FIO VARCHAR (30) NULL,
    ADRESS VARCHAR (30) NULL,
    PRIMARY KEY (ID_SELLER),
);

CREATE TABLE Zakaz_(
    ID_ZAKAZ INT NOT NULL,
    DATE_ DATE NULL,
    ID_SELLER INT NOT NULL FOREIGN KEY REFERENCES Seller_(ID_SELLER) 
    PRIMARY KEY (ID_ZAKAZ)
);

INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (111,'abcd1','Anton','derevnya universiady');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (112,'abcd2','Andrey','pushkina');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (113,'abcd3','Abdul','krasnaya pozitsiya');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (114,'abcd1','Alsu','derevnya universiady');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (115,'abcd2','Anna','pushkina');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (116,'abcd3','Azamat','krasnaya pozitsiya');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (117,'abcd2','Sergei','pushkina');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (118,'abcd1','Leysan','derevnya universiady');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (119,'abcd1','Katya','derevnya universiady');
INSERT INTO Seller_(ID_SELLER,PASS,FIO,ADRESS) VALUES (120,'abcd3','Anastasia','krasnaya pozitsiya');

INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (111,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (112,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (113,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (114,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (115,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (116,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (117,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (118,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (119,GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ,DATE_) VALUES (112,GETDATE());

我得到这个错误：

Msg 515, Level 16, State 2, Line 27
Cannot insert the value NULL into column 'ID_SELLER', table 'test.dbo.Zakaz_'; column does not allow nulls. INSERT fails.
The statement has been terminated.
Msg 515, Level 16, State 2, Line 28
Cannot insert the value NULL into column 'ID_SELLER', table 'test.dbo.Zakaz_'; column does not allow nulls. INSERT fails.
The statement has been terminated.
Msg 515, Level 16, State 2, Line 29
Cannot insert the value NULL into column 'ID_SELLER', table 'test.dbo.Zakaz_'; column does not allow nulls. INSERT fails.
...

---

为什么会出现此错误？我能做些什么？

Zakaz_uuu表中的ID_useller列必须包含SELLER_uu表中记录的ID。这样你就可以知道每个Zakaz与哪个卖家有关联

例如，尽管只有您可以确定正确的值，但这是可行的：

INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (111, 'abcd1', 'Anton', 'derevnya universiady');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (112, 'abcd2', 'Andrey', 'pushkina');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (113, 'abcd3', 'Abdul', 'krasnaya pozitsiya');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (114, 'abcd1', 'Alsu', 'derevnya universiady');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (115, 'abcd2', 'Anna', 'pushkina');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (116, 'abcd3', 'Azamat', 'krasnaya pozitsiya');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (117, 'abcd2', 'Sergei', 'pushkina');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (118, 'abcd1', 'Leysan', 'derevnya universiady');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (119, 'abcd1', 'Katya', 'derevnya universiady');
INSERT INTO Seller_(ID_SELLER, PASS, FIO, ADRESS) VALUES (120, 'abcd3', 'Anastasia', 'krasnaya pozitsiya');

INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (201, 111, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (202, 112, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (203, 113, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (204, 114, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (205, 115, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (206, 116, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (207, 117, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (208, 118, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (209, 119, GETDATE());
INSERT INTO Zakaz_(ID_ZAKAZ, ID_SELLER, DATE_) VALUES (210, 112, GETDATE());

请参阅我在两个表中的ID_卖方值（111112，…）中使用相同ID的方式，以便在它们之间建立关系

请参见结果：

SELECT * FROM Seller_;

ID_SELLER   PASS     FIO                            ADRESS
----------- -------- ------------------------------ ------------------------------
111         abcd1    Anton                          derevnya universiady
112         abcd2    Andrey                         pushkina
113         abcd3    Abdul                          krasnaya pozitsiya
114         abcd1    Alsu                           derevnya universiady
115         abcd2    Anna                           pushkina
116         abcd3    Azamat                         krasnaya pozitsiya
117         abcd2    Sergei                         pushkina
118         abcd1    Leysan                         derevnya universiady
119         abcd1    Katya                          derevnya universiady
120         abcd3    Anastasia                      krasnaya pozitsiya

SELECT * FROM Zakaz_;

ID_ZAKAZ    DATE_      ID_SELLER
----------- ---------- -----------
201         2019-12-19 111
202         2019-12-19 112
203         2019-12-19 113
204         2019-12-19 114
205         2019-12-19 115
206         2019-12-19 116
207         2019-12-19 117
208         2019-12-19 118
209         2019-12-19 119
210         2019-12-19 112

您现在甚至可以加入这些表：

SELECT * 
FROM Seller_ s
INNER JOIN Zakaz_ z
    on s.ID_SELLER = z.ID_SELLER;

ID_SELLER   PASS     FIO                            ADRESS                         ID_ZAKAZ    DATE_      ID_SELLER
----------- -------- ------------------------------ ------------------------------ ----------- ---------- -----------
111         abcd1    Anton                          derevnya universiady           201         2019-12-19 111
112         abcd2    Andrey                         pushkina                       202         2019-12-19 112
113         abcd3    Abdul                          krasnaya pozitsiya             203         2019-12-19 113
114         abcd1    Alsu                           derevnya universiady           204         2019-12-19 114
115         abcd2    Anna                           pushkina                       205         2019-12-19 115
116         abcd3    Azamat                         krasnaya pozitsiya             206         2019-12-19 116
117         abcd2    Sergei                         pushkina                       207         2019-12-19 117
118         abcd1    Leysan                         derevnya universiady           208         2019-12-19 118
119         abcd1    Katya                          derevnya universiady           209         2019-12-19 119
112         abcd2    Andrey                         pushkina                       210         2019-12-19 112