Oracle 表中缺少右括號錯誤

Question

CREATE TABLE Countries
    (CountryID INT NOT NULL PRIMARY KEY,
    CountryName VARCHAR2(100) NOT NULL,
    RegionID INT FOREIGN KEY REFERENCES Regions(RegionID)
    );

一直向我拋出這個： ORA-00907: missing right parenthesis

我做錯了什么？

Answer 1

內聯外鍵語法不采用FOREIGN KEY關鍵字。

考慮：

CREATE TABLE Countries (
    CountryID INT NOT NULL PRIMARY KEY,
    CountryName VARCHAR2(100) NOT NULL,
    RegionID INT REFERENCES Regions(RegionID)
);

或者，您可以在另一行聲明外鍵，如下所示：

CREATE TABLE Countries (
    CountryID INT NOT NULL PRIMARY KEY,
    CountryName VARCHAR2(100) NOT NULL,
    RegionID INT,
    CONSTRAINT fkRegionID FOREIGN KEY (RegionID) REFERENCES Regions(RegionID)
);

這也有效：

CREATE TABLE Countries (
    CountryID INT NOT NULL PRIMARY KEY,
    CountryName VARCHAR2(100) NOT NULL,
    RegionID INT,
    FOREIGN KEY (RegionID) REFERENCES Regions(RegionID)
);

DB Fiddle 上的演示