复合主键的外键和另一个属性

Question

我关注的table：

CREATE TABLE Branch(
    branchID        varchar(5) PRIMARY KEY,
    branchName      varchar(100),
    city            varchar(100),
    phone           varchar(15)
)Engine=InnoDB;

CREATE TABLE Theatre(
    theatreID       varchar(5),
    branchID        varchar(5),
    theatreType     varchar(50),
    rowCapacity     INT,
    seatCapacity    INT,

    FOREIGN KEY(branchID) REFERENCES Branch(branchID),
    PRIMARY KEY(theatreID,branchID)
)Engine=InnoDB;

CREATE TABLE Day(
    dayID           varchar(4) PRIMARY KEY,
    dayName         varchar(20),
    dayPrice        int
)Engine=InnoDB;

CREATE TABLE Price(
    theatreID       varchar(5),
    branchID        varchar(5),
    theatreType     varchar(50),
    moviePrice      INT,
    dayID           varchar(4),
    FOREIGN KEY(theatreID,branchID,theatreType) 
        REFERENCES Theatre(theatreID,branchID,theatreType),
    FOREIGN key(dayID) REFERENCES Day(dayID),
    PRIMARY KEY(branchID,dayID,theatreType)
)Engine=InnoDB;

我了解到引用具有复合主键的 table 的外键需要具有所述复合主键的所有属性。

这意味着 link table 剧院和价格，我必须添加

FOREIGN KEY(theatreID,branchID) 
        REFERENCES Theatre(theatreID,branchID)

代码仍然有效。

但是，如果我想添加另一个外键，'theatreType'。它 returns 错误 1005。

    FOREIGN KEY(theatreID,branchID,theatreType) 
        REFERENCES Theatre(theatreID,branchID,theatreType)

我哪里做错了？提前致谢。

Answer 1

外键和引用键需要具有相同的结构。如果您按以下方式更新 Theatre table，它将起作用

CREATE TABLE Theatre(
    theatreID       varchar(5),
    branchID        varchar(5),
    theatreType     varchar(50),
    rowCapacity     INT,
    seatCapacity    INT,

    FOREIGN KEY(branchID) REFERENCES Branch(branchID),
    PRIMARY KEY(theatreID,branchID,theatreType)
)Engine=InnoDB;

复合主键的外键和另一个属性

Foreign Key of Composite Primary Key and Another Attribute

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foreign-keys

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