Oracle SQL分類子類型

Question

CREATE TABLE Customer 
(
CustomerID NUMBER NOT NULL, 
AccountID NUMBER(10) NOT NULL, 
CustomerType VARCHAR(10) NOT NULL, 
CustomerStatus VARCHAR(10) NOT NULL, 
CONSTRAINT customer_pk PRIMARY KEY (CustomerID), 
CONSTRAINT check_customer_status CHECK(CustomerStatus IN ('Ineligible', 'Eligible')), 
CONSTRAINT check_customer_type CHECK(CustomerType IN ('NonResident', 'Residential')) 
); 

Alter table CUSTOMER add CONSTRAINT res_customer_type UNIQUE (CustomerID, CustomerType) 

CREATE TABLE nonresidential 
(
CustomerID NUMBER NOT NULL, 
CustomerType VARCHAR(10) NOT NULL, 
BusinessName VARCHAR(10) NOT NULL, 
ABNNumber NUMBER(10), 
Email VARCHAR(35), 
CONSTRAINT pk_nrtable PRIMARY KEY (CustomerID), 
CONSTRAINT nonres_type CHECK (CustomerType = 'nonresident'), 
CONSTRAINT res_customer_type UNIQUE (CustomerID, CustomerType) REFERENCES Customer(CustomerID, CustomerType) 
); 

最後一行繼續作爲缺少的括號（圍繞唯一約束的引用行）出現。我想指定唯一約束來在客戶下創建子類型表。

P.S我使用Oracle SQL，感謝

Answer 1

您可以使用獨特的關鍵字，你應該使用外鍵關鍵字。

CONSTRAINT res_customer_type UNIQUE (CustomerID, CustomerType) REFERENCES Customer(CustomerID, CustomerType) 

應該

CONSTRAINT res_customer_type FOREIGN KEY (CustomerID, CustomerType) REFERENCES Customer(CustomerID, CustomerType)