违反完整性约束 (SYSTEM.FK_FACILITY) - 未找到父键

Question

我收到“违反完整性约束 (SYSTEM.FK_FACILITY) - 未找到父键”错误，尽管主键已在上表中明确定义。

CREATE TABLE Facility (
  facNo   CHAR(11)    NOT NULL,
  facName VARCHAR(30) NOT NULL,
  CONSTRAINT FacilityPK PRIMARY KEY (facNo)
);
INSERT INTO Facility (facNo, facName) VALUES ('F100', 'Football stadium');
INSERT INTO Facility (facNo, facName) VALUES ('F101', 'Basketball arena');

CREATE TABLE Customer (
  custNo   CHAR(8)     NOT NULL,
  custName VARCHAR(30) NOT NULL,
  address  VARCHAR(50) NOT NULL,
  internal CHAR(10)     NOT NULL,
  city     VARCHAR(30) NOT NULL,
  zip      VARCHAR(10) NOT NULL,
  state1    VARCHAR(2)  NOT NULL,
  contact  VARCHAR(50) NOT NULL,
  phone    VARCHAR(30) NOT NULL,
  CONSTRAINT CustomerPk PRIMARY KEY (custNo)
);


INSERT INTO Customer (custNo, custName, address, internal, city, zip, state1, contact, phone) VALUES
  ('C100', 'Football', 'Box 352200', 'True', 'Boulder', '80309', 'CO', 'Mary Manager', '6857100');
INSERT INTO Customer (custNo, custName, address, internal, city, zip, state1, contact, phone) VALUES
  ('C101', 'Men''s Basketball', 'Box 352400', 'TRUE' , 'Boulder', '80309', 'CO', 'Sally Supervisor', '5431700');


CREATE TABLE EventReq (
  evntNo      CHAR(8)       NOT NULL,
  custNo      CHAR(8)       NOT NULL,
  facNo       CHAR(8)       NOT NULL,
  dateHeld    DATE          NOT NULL,
  dateReq     DATE          NOT NULL,
  dateAuth    DATE,
  status      CHAR(20)      NOT NULL,
  estCost     DECIMAL(8, 2) NOT NULL,
  estAudience INTEGER       NOT NULL,
  budNo       CHAR(30),
  CONSTRAINT EventReqtPK PRIMARY KEY (evntNo),
  CONSTRAINT FK_Facility FOREIGN KEY (facNo) REFERENCES Facility (facNo),
  CONSTRAINT FK_Customer FOREIGN KEY (custNo) REFERENCES Customer (custNo)

);

INSERT INTO EventReq (evntNo, custNo, facNo, dateHeld, dateReq, dateAuth, status, estCost, estAudience, budNo)
VALUES ('E100', 'C100', 'F100', TO_DATE('2013-10-25','YYYY-MM-DD'), TO_DATE('2013-06-06','YYYY-MM-DD'), TO_DATE('2013-06-08','YYYY-MM-DD'), 'Approved', 5000.00, 80000, 'B1000');

我的确切错误是

INSERT INTO EventReq (evntNo, custNo, facNo, dateHeld, dateReq, dateAuth, status, estCost, estAudience, budNo)
VALUES ('E100', 'C100', 'F100', TO_DATE('2013-10-25','YYYY-MM-DD'), TO_DATE('2013-06-06','YYYY-MM-DD'), TO_DATE('2013-06-08','YYYY-MM-DD'), 'Approved', 5000.00, 80000, 'B1000')
Error report -
ORA-02291: integrity constraint (SYSTEM.FK_FACILITY) violated - parent key not found

我只想将值添加到表中，但我无法这样做... 如果有人可以帮助我，那就太好了！

Answer 1

CHAR 是一个糟糕的选择，除非您知道所有值都是固定长度的。为什么？因为 Oracle 用空格右填充这些值，直到最大列长度。

这就是你所做的：

SQL> desc facility;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 FACNO                                     NOT NULL CHAR(11)           --> 11 characters
 FACNAME                                   NOT NULL VARCHAR2(30)

SQL> select facno, length(facno) lenfac, 'x' || facno ||'x' xfac from facility;

FACNO           LENFAC XFAC
----------- ---------- -------------
F100                11 xF100       x
F101                11 xF101       x      
                            -------
                            1234567 spaces
SQL>

看到了吗？

• 列长 = 11
• 您存储的值是F100
• 存储为F100 + 7个空格，共11个字符

在插入eventreq 表时不会出现问题，但是 - 你说它在facno 列中接受 11 个字符：

SQL> desc eventreq
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EVNTNO                                    NOT NULL CHAR(8)
 CUSTNO                                    NOT NULL CHAR(8)
 FACNO                                     NOT NULL CHAR(8)         --> 8 characters
 DATEHELD                                  NOT NULL DATE
 DATEREQ                                   NOT NULL DATE
 DATEAUTH                                           DATE
 STATUS                                    NOT NULL CHAR(20)
 ESTCOST                                   NOT NULL NUMBER(8,2)
 ESTAUDIENCE                               NOT NULL NUMBER(38)
 BUDNO                                              CHAR(30)

SQL>

这意味着 - 当您在 eventreq 表中插入一行时，facno = F100 右侧填充了最多列长度为 8 个字符的空格（即 @ 987654330@ + 4 个空格）。

比较：

facility - facno char(11)
eventreq - facno char(8)

F100 右填充 8 个字符与 F100 右填充 11 个字符不同，这就是 Oracle 说找不到匹配的父键的原因。

怎么办？

• 将facility 表中的facno 列缩短为8 个字符
  • 或将eventreq 中的该列放大到11 个字符
• 将数据类型更改为VARCHAR2

例如，如果两列都是CHAR(8)：

SQL> desc facility
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 FACNO                                     NOT NULL CHAR(8)
 FACNAME                                   NOT NULL VARCHAR2(30)

SQL> select * From facility;

FACNO    FACNAME
-------- ------------------------------
F100     Football stadium

SQL> desc eventreq;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EVNTNO                                    NOT NULL CHAR(8)
 CUSTNO                                    NOT NULL CHAR(8)
 FACNO                                     NOT NULL CHAR(8)
 DATEHELD                                  NOT NULL DATE
 DATEREQ                                   NOT NULL DATE
 DATEAUTH                                           DATE
 STATUS                                    NOT NULL CHAR(20)
 ESTCOST                                   NOT NULL NUMBER(8,2)
 ESTAUDIENCE                               NOT NULL NUMBER(38)
 BUDNO                                              CHAR(30)

SQL> INSERT INTO EventReq (evntNo, custNo, facNo, dateHeld, dateReq, dateAuth, status, estCost, estAudience, budNo)
  2  VALUES ('E100', 'C100', 'F100', TO_DATE('2013-10-25','YYYY-MM-DD'), TO_DATE('2013-06-06','YYYY-MM-DD'), TO_DATE('2013-06-08','YYYY-MM-DD'), 'Appr
oved', 5000.00, 80000, 'B1000');

1 row created.

SQL>

它有效。

---

最后，一个巨大的错误：

SYSTEM.FK_FACILITY

不要将SYSTEM（或SYS）用户用于数据库管理以外的任何事情。它们不适合用于像您这样的目的。