未正确使用外键的 SQL 错误“未找到父键”？

【问题标题】：SQL Error 'Parent Key Not Found' for Improperly Used Foreign Keys?未正确使用外键的 SQL 错误“未找到父键”？
【发布时间】：2018-10-29 12:56:31
【问题描述】：

我更新了我的尝试，将一些内容保留为 CHAR，但仍然收到类似的错误：第 1 行的错误： ORA-02091: 事务回滚 ORA-02291: 违反完整性约束 (MMM1339.ITEMNO_PHAR_FK) - 未找到父键

申请的外键在不同的供应主键中都有值，所以我不确定为什么仍然存在问题。 

CREATE TABLE SUPPLIER
(SUPPLIERNO   CHAR(6),
 SUPPLIERNAME VARCHAR2(100),
 PHONENO VARCHAR2(12),
 ADDRESS VARCHAR(100),
 FAXNO VARCHAR(12),
 CONSTRAINT SUPPLIERNO_SSPL_PK PRIMARY KEY(SUPPLIERNO));

CREATE TABLE SUPPLIES_PHARMACEUTICAL
(ITEMNO         CHAR(6),
SUPPLIERNO      CHAR(6),
NAME            VARCHAR2(25),
DESCRIPTION     VARCHAR2(25),
QUANTITYINSTOCK INT,
REORDERLEVEL    INT,
COSTPERUNIT     DECIMAL(6,2),
DOSAGE          VARCHAR2(12),
CONSTRAINT ITEMNO_PHAR_PK PRIMARY KEY(ITEMNO));

CREATE TABLE SUPPLIES_SURGICAL
(ITEMNO         CHAR(6),
NAME            VARCHAR2(25),
DESCRIPTION     VARCHAR2(25),
QUANTITYINSTOCK INT,
REORDERLEVEL    INT,
COSTPERUNIT     DECIMAL(6,2),
SUPPLIERNO      CHAR(6),
CONSTRAINT ITEMNO_SUP_PK PRIMARY KEY(ITEMNO));

CREATE TABLE SUPPLIES_NONSURGICAL
(ITEMNO         CHAR(6),
NAME            VARCHAR2(25),
DESCRIPTION     VARCHAR2(25),  
QUANTITYINSTOCK INT,
REORDERLEVEL    INT,
COSTPERUNIT     DECIMAL(6,2),
SUPPLIERNO      CHAR(6),
CONSTRAINT ITEMNO_NONSURG_PK PRIMARY KEY(ITEMNO));

CREATE TABLE STAFF_CHARGENURSE
(STAFFNO   CHAR(6),
 ADDRESS   VARCHAR2(25),
 POSITION  VARCHAR2(12),
 BUDGET    DECIMAL(6,2),
 SPECIALTY VARCHAR2(12),
 CONSTRAINT STAFFNO_CHNURSE_PK PRIMARY KEY(STAFFNO));

 CREATE TABLE REQUISITION
 (REQNO CHAR(6),
  STAFFNO CHAR(6),
  STAFFNAME VARCHAR2(25),
  WARDNO CHAR(6),
  ITEMNO CHAR(6),
  QUANTITY INT,
  DATEORDERED DATE,
  DATERECIEVED DATE,
  CONSTRAINT REQ_PK PRIMARY KEY(REQNO));

 ALTER TABLE SUPPLIES_PHARMACEUTICAL ADD CONSTRAINT SUPPLIERNO_PHA_FK FOREIGN KEY(SUPPLIERNO) REFERENCES SUPPLIER(SUPPLIERNO) DEFERRABLE INITIALLY DEFERRED;
 ALTER TABLE SUPPLIES_SURGICAL ADD CONSTRAINT SUPPLIERNO_SURG_FK FOREIGN KEY(SUPPLIERNO) REFERENCES SUPPLIER(SUPPLIERNO) DEFERRABLE INITIALLY DEFERRED;
 ALTER TABLE SUPPLIES_NONSURGICAL ADD CONSTRAINT SUPPLIERNO_NONSURG_FK FOREIGN KEY(SUPPLIERNO) REFERENCES SUPPLIER(SUPPLIERNO) DEFERRABLE INITIALLY DEFERRED;
 ALTER TABLE REQUISITION ADD CONSTRAINT STAFFNO_REQ_FK FOREIGN KEY(STAFFNO) REFERENCES STAFF_CHARGENURSE(STAFFNO) DEFERRABLE INITIALLY DEFERRED;
 ALTER TABLE REQUISITION ADD CONSTRAINT ITEMNO_PHAR_FK FOREIGN KEY(ITEMNO) REFERENCES SUPPLIES_PHARMACEUTICAL(ITEMNO) DEFERRABLE INITIALLY DEFERRED;
 ALTER TABLE REQUISITION ADD CONSTRAINT ITEMNO_SURG_FK FOREIGN KEY(ITEMNO) REFERENCES SUPPLIES_SURGICAL(ITEMNO) DEFERRABLE INITIALLY DEFERRED;
 ALTER TABLE REQUISITION ADD CONSTRAINT ITEMNO_NONSURG_FK FOREIGN KEY(ITEMNO) REFERENCES SUPPLIES_NONSURGICAL(ITEMNO) DEFERRABLE INITIALLY DEFERRED;

 INSERT INTO REQUISITION VALUES('000001', '345000', 'Julie Wood', '8', '888520', 2, '27-FEB-2018', '15-MAR-2018');
 INSERT INTO REQUISITION VALUES('000002', '345000', 'Julie Wood', '8', '923956', 1, '25-FEB-2018', '28-FEB-2018');
 INSERT INTO REQUISITION VALUES('000003', '345000', 'Julie Wood', '8', '054802', 3, '20-FEB-2018', '22-FEB-2018');

 INSERT INTO SUPPLIES_PHARMACEUTICAL VALUES ('823456', '100001', 'Zanax', 'Anti Depressant', 8, 2, 100.50, '50mg');
 INSERT INTO SUPPLIES_PHARMACEUTICAL VALUES ('923956', '100001', 'Zupridol', 'Blood Pressure Treatment', 12, 5, 50, '20mg');
 INSERT INTO SUPPLIES_PHARMACEUTICAL VALUES ('003952', '200001', 'Amibreezax', 'Antifungal Ear Wax', 2, 1, 200, '5g');
 INSERT INTO SUPPLIES_PHARMACEUTICAL VALUES ('004955', '200001', 'Ambridax', 'Blood Fungus Treatment', 5, 10, 20, '2mg');

 INSERT INTO SUPPLIES_SURGICAL VALUES ('054802', 'Scalpel', 'Scalping Tool', 20, 10, 200.42, '100001');
 INSERT INTO SUPPLIES_SURGICAL VALUES ('634520', 'Stitches', 'Suture Tool', 100, 10, 2.50, '200001');

 INSERT INTO SUPPLIES_NONSURGICAL VALUES ('888520', 'Cart', '5ftx2ftx3ft', 2, 0, 200.00, '100001');
 INSERT INTO SUPPLIES_NONSURGICAL VALUES ('000423', 'Tool Holder', 'Holds Inspection Equip.', 4, 2, 50.00, '100001');

 INSERT INTO STAFF_CHARGENURSE VALUES('345000', '32 Stark St. Portland, OR', 'Charge Nurse', 8000.99, 'Head Trauma');
 INSERT INTO STAFF_CHARGENURSE VALUES('246000', '18 Wilson Rd Portland, OR', 'Charge Nurse', 6000, 'Epidermus');

 INSERT INTO SUPPLIER VALUES ('100001','Company A', '503-222-3333', '100 SE Stark Rd Portland, OR', '503-666-4444');
 INSERT INTO SUPPLIER VALUES ('200001','Company B', '666-333-4444', '500 SE Bilerica Rd Akron, OH', '666-444-3333');

 COMMIT;

【问题讨论】：

  • 我从未听说过MANDATORY, OR，但看起来您的三个 SUPPLIES 表应该是一个带有分类列的表。不过，我对这些分类有点困惑——药物、手术和非手术。手术和非手术不应该涵盖一切吗？顺便说一句，所有这些CHR 列都应该是VARCHAR2。

标签： sql oracle foreign-keys


【解决方案1】：

此答案与您的问题有关，即为什么您更新的具有延迟约束的定义仍然会违反 FK。

在插入行之后但在尝试提交之前：

select r.reqno, r.itemno
     , sp.name as pharmaceutical
     , ss.name as surgical
     , sn.name as nonsurgical
from   requisition r
       left join supplies_pharmaceutical sp on sp.itemno = r.itemno
       left join supplies_surgical ss on ss.itemno = r.itemno
       left join supplies_nonsurgical sn on sn.itemno = r.itemno;

REQNO   ITEMNO  PHARMACEUTICAL  SURGICAL        NONSURGICAL
------- ------- --------------- --------------- ---------------
000001  888520                                  Cart
000002  923956  Zupridol                        
000003  054802                  Scalpel

项目888520违反约束ITEMNO_PHAR_FK，因为它没有在父表SUPPLIES_PHARMACEUTICAL中定义：

ALTER TABLE REQUISITION ADD CONSTRAINT ITEMNO_PHAR_FK
    FOREIGN KEY(ITEMNO) REFERENCES SUPPLIES_PHARMACEUTICAL(ITEMNO) ...

这也违反了ITEMNO_SURG_FK，因为888520不在父表SUPPLIES_SURGICAL中：

ALTER TABLE REQUISITION ADD CONSTRAINT ITEMNO_SURG_FK
    FOREIGN KEY(ITEMNO) REFERENCES SUPPLIES_SURGICAL(ITEMNO) ...

等等。每个申请行违反两个约束。将约束定义为 deferred 不会改变任何东西，除了错误的时间。

为了满足您的 FK 定义，每个 itemno 都需要存在于所有三个供应表中。

如果您确实需要三个供应表，则需要三个单独的供应项目列，每个列都有对应表的 FK。

（你真的应该将那些 CHAR 列更改为标准字符串类型。CHAR 在 Oracle 数据库中没有位置，它纯粹是为了奇怪的可移植性和 ANSI 完整性要求，而不是你实际应该使用的类型.)

【讨论】：

    【解决方案2】：

    已编辑：

    将SUPPLIES_SURGICAL 和SUPPLIES_NONSURGICAL 组合为一个SUPPLIES 表，并将PHARMA_DOSAGE 定义为该表下的子表。

    现在SUPPLIES 行必须是外科手术或非外科手术，这可以实现为 Y/N 标志并由检查约束强制执行。 （不过，一个可能的问题是该模型不会阻止您为手术项目添加剂量。）

    在下文中，我将 ITEMNO 设为整数并修复了您的 CHAR 列。您可以考虑查看以NO 结尾的所有列的数据类型，特别是如果它们要按顺序生成。我也会制作所有生成的 PK 列标识列，但我将把细节留给你。

    create table supplier
( supplierno      integer primary key );

create table supplies
( itemno          integer
                  constraint supplies_pk primary key
, supplierno      constraint supplies_supplier_fk references supplier(supplierno)
, name            varchar2(25) not null
, description     varchar2(25) null
, quantityinstock integer
, reorderlevel    integer
, costperunit     number(6,2)
, is_surgical     varchar2(1) not null
                  constraint supplies_surgical_yn_chk check(is_surgical in ('Y','N')) );

create table pharma_dosage
( itemno          constraint pharma_supplies_fk references supplies(itemno)
                  constraint pharma_supplies_pk primary key
, dosage          varchar2(12) not null );

create table staff_chargenurse
( staffno         varchar2(6)
                  constraint staffno_chnurse_pk primary key
, address         varchar2(25)
, position        varchar2(12)
, budget          number(6,2)
, specialty       varchar2(12) );

create table requisition
( reqno           varchar2(6)
                  constraint reqno_pk primary key
, staffno         constraint staffno_req_fk references staff_chargenurse(staffno)
, staffname       varchar2(25)
, wardno          varchar2(6)
, itemno          constraint itemno_supplies_fk references supplies(itemno)
, quantity        integer
, dateordered     date
, daterecieved    date );

insert into supplier values ('100001');
insert into supplier values ('200001');

insert into supplies (itemno, supplierno, name, description, quantityinstock, reorderlevel, costperunit, is_surgical) values (823456, '100001', 'Zanax', 'Anti Depressant', 8, 2, 100.50, 'N');
insert into supplies (itemno, supplierno, name, description, quantityinstock, reorderlevel, costperunit, is_surgical) values (923956, '100001', 'Zupridol', 'Blood Pressure Treatment', 12, 5, 50, 'N');
insert into supplies (itemno, supplierno, name, description, quantityinstock, reorderlevel, costperunit, is_surgical) values (003952, '200001', 'Amibreezax', 'Antifungal Ear Wax', 2, 1, 200, 'N');
insert into supplies (itemno, supplierno, name, description, quantityinstock, reorderlevel, costperunit, is_surgical) values (004955, '200001', 'Ambridax', 'Blood Fungus Treatment', 5, 10, 20, 'N');

insert into pharma_dosage (itemno, dosage) values (823456, '50mg');
insert into pharma_dosage (itemno, dosage) values (923956, '20mg');
insert into pharma_dosage (itemno, dosage) values (003952, '5g');
insert into pharma_dosage (itemno, dosage) values (004955, '2mg');

insert into supplies (itemno, name, description, quantityinstock, reorderlevel, costperunit, supplierno, is_surgical) values (054802, 'Scalpel', 'Scalping Tool', 20, 10, 200.42, '100001', 'Y');
insert into supplies (itemno, name, description, quantityinstock, reorderlevel, costperunit, supplierno, is_surgical) values (634520, 'Stitches', 'Suture Tool', 100, 10, 2.50, '200001', 'Y');

insert into supplies (itemno, name, description, quantityinstock, reorderlevel, costperunit, supplierno, is_surgical) values (888520, 'Cart', '5ftx2ftx3ft', 2, 0, 200.00, '100001', 'N');
insert into supplies (itemno, name, description, quantityinstock, reorderlevel, costperunit, supplierno, is_surgical) values (000423, 'Tool Holder', 'Holds Inspection Equip.', 4, 2, 50.00, '100001', 'N');

insert into staff_chargenurse values('345000', '32 Stark St. Portland, OR', 'Charge Nurse', 8000.99, 'Head Trauma');
insert into staff_chargenurse values('246000', '18 Wilson Rd Portland, OR', 'Charge Nurse', 6000, 'Epidermus');

insert into requisition (reqno, staffno, staffname, wardno, itemno, quantity, dateordered, daterecieved) values('000001', '345000', 'Julie Wood', '8', 888520, 2, date '2018-02-27', date '2018-03-15');
insert into requisition (reqno, staffno, staffname, wardno, itemno, quantity, dateordered, daterecieved) values('000002', '345000', 'Julie Wood', '8', 823456, 1, date '2018-02-25', date '2018-02-28');
insert into requisition (reqno, staffno, staffname, wardno, itemno, quantity, dateordered, daterecieved) values('000003', '345000', 'Julie Wood', '8', 054802, 3, date '2018-02-20', date '2018-02-22');

    【讨论】：

    • 真的很欣赏这个版本，威廉。问题是我的关系模型要求我有多个外键。
    • 不确定您的关系模型是什么意思，或者您面临的设计限制。我的建议包括修改您的数据模型。
    【解决方案3】：

    不幸的是（对于您的 DDL 代码）我必须同意@William Robertson - 您需要更改您的模型，因此您需要完全重新编写您的 DDL 代码。原因如下：

    查看逆向工程模型，从您的原始 DDL 代码中，我们可以看到 REQUISITION 有 3 个（抱歉，4 个）父表。这就是为什么它的插入总是失败，因为外键违规。您的型号：

    以 DDL 代码形式说明问题的简化示例可能如下所示：

    create table parent1 ( id number primary key ) ; -- analogy: supplies_pharmaceutical
create table parent2 ( id number primary key ) ; -- analogy: supplies_nonsurgical
create table parent3 ( id number primary key ) ; -- analogy: supplies_surgical

create table child ( -- analogy: requisitions
  id number primary key
, parentid number 
);

alter table child add constraint fkey_parent1
foreign key ( parentid ) references parent1 ( id ) ;

alter table child add constraint fkey_parent2
foreign key ( parentid ) references parent2 ( id ) ;

alter table child add constraint fkey_parent3
foreign key ( parentid ) references parent3 ( id ) ;

begin
  insert into parent1 ( id ) values ( 1 ) ;
  insert into parent2 ( id ) values ( 2 ) ;
  insert into parent3 ( id ) values ( 3 ) ;
end ;
/

    因此，在填充了我们的父表后，只需快速检查一下：

    select 'parent1 (id) -> ' || id from parent1
union all
select 'parent2 (id) -> ' ||  id from parent2
union all
select 'parent3 (id) -> ' ||  id from parent3
;

-- result
'PARENT1(ID)->'||ID  
parent1 (id) -> 1    
parent2 (id) -> 2    
parent3 (id) -> 3

    一切都好。现在我们想在我们的子表中插入一些行。

    insert into child ( id, parentid ) values ( 100, 1 ) ;
-- ORA-02291: integrity constraint (...FKEY_PARENT3) violated - parent key not found

insert into child ( id, parentid ) values ( 101, 2 ) ;
-- ORA-02291: integrity constraint (...FKEY_PARENT3) violated - parent key not found

insert into child ( id, parentid ) values ( 102, 3 ) ;
-- ORA-02291: integrity constraint (...FKEY_PARENT2) violated - parent key not found

    您会看到正确的父表不只是“自动选择”。

    在 William 的模型 OTOH 中，REQUISITION 关于“供应”只有一个父级（表）。这应该使插入行更容易......见下文。

    【讨论】：

      【解决方案4】：

      我们需要重新安排以抑制 ORA-02291 错误：

      • 首先，INSERT 语句应该以 分号。
      • 应该有一个名为 SUPPLIER 的表被引用。

      • 创建没有FOREIGN KEYS的表，并且在所有这些表都创建之后， ALTER 表以包含 外键。 为了抑制 INSERT 操作期间的数据不一致，我们需要将 FOREIGN KEYS 创建为 DEFERRABLE INITIALLY DEFERRED（通过以下方式，即使当结束 COMMIT 已发布）。

        我认为，您最好将 SUPPLIERNO 列存储为 INT(EGER) 或 NUMBER，而不是 CHAR时间>。此外，CHAR 数据类型已被弃用，最好将它们转换为 VARCHAR2。

      因此，使用以下一系列操作（在底部，我更改了 REQUISITION 的一些值，以免违反 Foreign Constraints）：

          CREATE TABLE SUPPLIER
    (SUPPLIERNO   INT,
     SUPPLIERNAME VARCHAR2(100),
     CONSTRAINT SUPPLIERNO_SSPL_PK PRIMARY KEY(SUPPLIERNO));

    CREATE TABLE SUPPLIES_PHARMACEUTICAL
    (ITEMNO         INT,
    SUPPLIERNO      INT,
    NAME            VARCHAR2(25),
    DESCRIPTION     VARCHAR2(25),
    QUANTITYINSTOCK INT,
    REORDERLEVEL    INT,
    COSTPERUNIT     DECIMAL(6,2),
    DOSAGE          VARCHAR2(12),
    CONSTRAINT ITEMNO_PHAR_PK PRIMARY KEY(ITEMNO));

    CREATE TABLE SUPPLIES_SURGICAL
    (ITEMNO         INT,
    NAME            VARCHAR2(25),
    DESCRIPTION     VARCHAR2(25),
    QUANTITYINSTOCK INT,
    REORDERLEVEL    INT,
    COSTPERUNIT     DECIMAL(6,2),
    SUPPLIERNO      INT,
    CONSTRAINT ITEMNO_SUP_PK PRIMARY KEY(ITEMNO));

    CREATE TABLE SUPPLIES_NONSURGICAL
    (ITEMNO         INT,
    NAME            VARCHAR2(25),
    DESCRIPTION     VARCHAR2(25),  
    QUANTITYINSTOCK INT,
    REORDERLEVEL    INT,
    COSTPERUNIT     DECIMAL(6,2),
    SUPPLIERNO      INT,
    CONSTRAINT ITEMNO_NONSURG_PK PRIMARY KEY(ITEMNO));

    CREATE TABLE STAFF_CHARGENURSE
    (STAFFNO   INT,
     ADDRESS   VARCHAR2(25),
     POSITION  VARCHAR2(12),
     BUDGET    DECIMAL(6,2),
     SPECIALTY VARCHAR2(12),
     CONSTRAINT STAFFNO_CHNURSE_PK PRIMARY KEY(STAFFNO));

     ALTER TABLE SUPPLIES_PHARMACEUTICAL ADD CONSTRAINT SUPPLIERNO_PHA_FK FOREIGN KEY(SUPPLIERNO) REFERENCES SUPPLIER(SUPPLIERNO) DEFERRABLE INITIALLY DEFERRED;
     ALTER TABLE SUPPLIES_SURGICAL ADD CONSTRAINT SUPPLIERNO_SURG_FK FOREIGN KEY(SUPPLIERNO) REFERENCES SUPPLIER(SUPPLIERNO) DEFERRABLE INITIALLY DEFERRED;
     ALTER TABLE SUPPLIES_NONSURGICAL ADD CONSTRAINT SUPPLIERNO_NONSURG_FK FOREIGN KEY(SUPPLIERNO) REFERENCES SUPPLIER(SUPPLIERNO) DEFERRABLE INITIALLY DEFERRED;

     INSERT INTO SUPPLIES_PHARMACEUTICAL VALUES (888520, 100001, 'Zanax', 'Anti Depressant', 8, 2, 100.50, '50mg');
     INSERT INTO SUPPLIES_PHARMACEUTICAL VALUES (923956, 100001, 'Zupridol', 'Blood Pressure Treatment', 12, 5, 50, '20mg');
     INSERT INTO SUPPLIES_PHARMACEUTICAL VALUES (634520, 200001, 'Amibreezax', 'Antifungal Ear Wax', 2, 1, 200, '5g');
     INSERT INTO SUPPLIES_PHARMACEUTICAL VALUES (4955, 200001, 'Ambridax', 'Blood Fungus Treatment', 5, 10, 20, '2mg');

     INSERT INTO SUPPLIES_SURGICAL VALUES (888520, 'Scalpel', 'Scalping Tool', 20, 10, 200.42, 100001);
     INSERT INTO SUPPLIES_SURGICAL VALUES (634520, 'Stitches', 'Suture Tool', 100, 10, 2.50, 200001);

     INSERT INTO SUPPLIES_NONSURGICAL VALUES (888520, 'Cart', '5ftx2ftx3ft', 2, 0, 200.00, 100001);
     INSERT INTO SUPPLIES_NONSURGICAL VALUES (634520, 'Tool Holder', 'Holds Inspection Equip.', 4, 2, 50.00, 100001);


     INSERT INTO STAFF_CHARGENURSE VALUES(345000, '32 Stark St. Portland, OR', 'Charge Nurse', 8000.99, 'Head Trauma');
     INSERT INTO STAFF_CHARGENURSE VALUES(246000, '18 Wilson Rd Portland, OR', 'Charge Nurse', 6000, 'Epidermus');

     INSERT INTO SUPPLIER VALUES (100001,'Company A');
     INSERT INTO SUPPLIER VALUES (200001,'Company B');

     CREATE TABLE REQUISITION
     (REQNO       INT,
     STAFFNO      INT,
     STAFFNAME    VARCHAR2(25),
     WARDNO       INT,
     ITEMNO       INT,
     QUANTITY     INT,
     DATEORDERED  DATE,
     DATERECIEVED DATE,
     CONSTRAINT REQNO_PK PRIMARY KEY(REQNO),
     CONSTRAINT STAFFNO_REQ_FK FOREIGN KEY(STAFFNO) REFERENCES STAFF_CHARGENURSE(STAFFNO),
     CONSTRAINT ITEMNO_PHAR_FK FOREIGN KEY(ITEMNO) REFERENCES SUPPLIES_PHARMACEUTICAL(ITEMNO),
     CONSTRAINT ITEMNO_SURG_FK FOREIGN KEY(ITEMNO) REFERENCES SUPPLIES_SURGICAL(ITEMNO),
     CONSTRAINT ITEMNO_NONSURG_FK FOREIGN KEY(ITEMNO) REFERENCES SUPPLIES_NONSURGICAL(ITEMNO));
     INSERT INTO REQUISITION VALUES(1, 345000, 'Julie Wood', 8, 888520, 2, '27-FEB-2018', '15-MAR-2018');
     INSERT INTO REQUISITION VALUES(2, 345000, 'Julie Wood', 8, 634520, 1, '25-FEB-2018', '28-FEB-2018');
     INSERT INTO REQUISITION VALUES(3, 345000, 'Julie Wood', 8, 634520, 3, '20-FEB-2018', '22-FEB-2018');

     COMMIT;

      【讨论】：

      • 感谢您提供的所有详细信息。不过，您能评论一下我遇到的问题吗？对于每个供应，他们可能有许多申请，这意味着持有 FK 的弱实体是申请，我觉得我对申请的更新在 3 个供应表中的 2 个中没有 PK 仍然会导致错误。如果 DEFERRABLE 解决了这个问题，你能帮我理解一下吗？
      • @MarkMcGown 不客气，我编辑了答案的朋友。
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