Question

我已经为父表编写了代码，但是当我尝试运行sql命令生成子表时，出现了匹配错误：

“此列列表没有匹配的唯一键或主键”

父表的生成如下：

CREATE TABLE dabel3_RetailCenter 
(store_id CHAR (4) NOT NULL, 
store_type VARCHAR2 (15) NOT NULL, 
store_st_num CHAR (4) NOT NULL,
store_st_name VARCHAR2 (50) NOT NULL, 
store_city VARCHAR2 (15) NOT NULL, 
store_state VARCHAR2 (12) NOT NULL, store_ZIP CHAR (5),
CONSTRAINT dabel3_store_id_pk PRIMARY KEY (store_id));

CREATE TABLE dabel3_Trans_Type (
TM_ID CHAR (2) NOT NULL, 
TM_Type VARCHAR2 (15) NOT NULL, 
CONSTRAINT dabel3_Trans_type_TM_ID_pk PRIMARY KEY (TM_ID), 
CONSTRAINT TM_Type_UNQ UNIQUE (TM_TYPE));

CREATE TABLE dabel3_Trans_Mode (
TM_ID CHAR (2) NOT NULL, 
TM_Route VARCHAR2 (15) NOT NULL, 
TM_Sched_Num CHAR (3) NOT NULL,
CONSTRAINT dabel3_Trans_mode_pk PRIMARY KEY (TM_ID, TM_Sched_Num), 
CONSTRAINT dabel3_trans_mode_TM_ID_fk FOREIGN KEY (TM_ID) REFERENCES dabel3_Trans_Type (TM_ID));

但是，子表不会生成。对我在做什么错有任何想法吗？

CREATE TABLE dabel3_Shipment (
pkg_track_num VARCHAR2 (15) NOT NULL, 
pkg_weight CHAR (7) NOT NULL, 
pkg_dimensions VARCHAR2 (20), 
pkg_insurance VARCHAR2 (50), 
pkg_dest_city VARCHAR2 (20) NOT NULL, 
pkg_dest_state CHAR (2) NOT NULL, 
pkg_dest_ZIP CHAR (5) NOT NULL, 
pkg_due_date DATE NOT NULL,
store_id CHAR (4) NOT NULL, 
TM_ID CHAR (2) NOT NULL, 
TM_Sched_Num CHAR (3) NOT NULL, 
CONSTRAINT dabel3_pkg_track_num_pk PRIMARY KEY (pkg_track_num), 
CONSTRAINT dabel3_shipment_store_id_fk FOREIGN KEY (store_id) REFERENCES dabel3_RetailCenter (store_id),
CONSTRAINT dabel3_shipment_TM_ID_fk FOREIGN KEY (TM_ID) REFERENCES dabel3_Trans_Type (TM_ID),
CONSTRAINT dabel3_shipment_TM_Sched_Num_fk FOREIGN KEY (TM_Sched_Num) REFERENCES dabel3_Trans_Mode (TM_Sched_Num));

Answer 1

如果遇到这样的问题，我会将失败的语句切成更易于调试的位：

CREATE TABLE dabel3_Shipment (
  pkg_track_num VARCHAR2 (15) NOT NULL, 
  pkg_weight CHAR (7) NOT NULL, 
  pkg_dimensions VARCHAR2 (20), 
  pkg_insurance VARCHAR2 (50), 
  pkg_dest_city VARCHAR2 (20) NOT NULL, 
  pkg_dest_state CHAR (2) NOT NULL, 
  pkg_dest_ZIP CHAR (5) NOT NULL, 
  pkg_due_date DATE NOT NULL,
  store_id CHAR (4) NOT NULL, 
  TM_ID CHAR (2) NOT NULL, 
  TM_Sched_Num CHAR (3) NOT NULL
);
Table DABEL3_SHIPMENT created

ALTER TABLE dabel3_Shipment ADD                       
  CONSTRAINT dabel3_pkg_track_num_pk PRIMARY KEY (pkg_track_num); 
Table DABEL3_SHIPMENT altered.

ALTER TABLE dabel3_Shipment ADD                                                     
  CONSTRAINT dabel3_shipment_store_id_fk FOREIGN KEY (store_id) 
  REFERENCES dabel3_RetailCenter (store_id);
Table DABEL3_SHIPMENT altered.

ALTER TABLE dabel3_Shipment ADD                                                     
  CONSTRAINT dabel3_shipment_TM_ID_fk FOREIGN KEY (TM_ID) 
  REFERENCES dabel3_Trans_Type (TM_ID);
Table DABEL3_SHIPMENT altered.

ALTER TABLE dabel3_Shipment ADD                                                     
  CONSTRAINT dabel3_sht_TM_Sched_Num_fk 
  FOREIGN KEY (TM_Sched_Num) 
  REFERENCES dabel3_Trans_Mode (TM_Sched_Num);
ORA-02270: no matching unique or primary key for this column

因此，此子句中有错误。在引用的列上没有主键或唯一键。一旦我们解决了这个问题...

ALTER TABLE dabel3_Trans_Mode ADD 
  CONSTRAINT dabel3_Trans_mode_sm_unq UNIQUE(TM_Sched_Num);
Table DABEL3_TRANS_MODE altered.

...约束编译：

ALTER TABLE dabel3_Shipment ADD                                                     
  CONSTRAINT dabel3_sht_TM_Sched_Num_fk 
  FOREIGN KEY (TM_Sched_Num) 
  REFERENCES dabel3_Trans_Mode (TM_Sched_Num);
Table DABEL3_SHIPMENT altered.

编辑：

@Impaler显然是正确的，复合键将是更好的解决方案。

Answer 2

上一次创建dabel3_Shipment的表的位置错误：

CONSTRAINT dabel3_shipment_TM_Sched_Num_fk 
FOREIGN KEY (TM_Sched_Num) 
REFERENCES dabel3_Trans_Mode (TM_Sched_Num) -- NOT a key

问题在于dabel3_Trans_Mode的列TM_Sched_Num不是键。为了建立外键，它必须指向到远程表中的键。

被引用的表具有组合键(TM_ID, TM_Sched_Num)。您正在尝试使用密钥的一部分，但这不是密钥。完整使用它，两列，问题都解决了。

例如，您可以这样做：

CONSTRAINT dabel3_shipment_TM_Sched_Num_fk 
FOREIGN KEY (TM_ID, TM_Sched_Num) 
REFERENCES dabel3_Trans_Mode (TM_ID, TM_Sched_Num)

此列列表没有唯一键或主键？

2 个答案: