具有两列组合的 SQLite 唯一键

Question

我试图确保当我运行以下查询时，只有第一个 INSERT INTO 会起作用。我知道我必须制作 slot UNIQUE

插槽可以是 0-5 INTEGER，但这并不意味着该表只能接受 6 个表数据行。

对于匹配的每个 playerHash，它应该只允许 6 表数据行，因为 slot 是 UNIQUE(对于每个 playerHash 列，不能有相同插槽列的副本)。

//Below Query Should Pass
INSERT INTO Buying(itemId, amount, price, bought, slot, playerHash) VALUES (1, 1, 1, 1, 1, 1);
//Below Query Should Fail
INSERT INTO Buying(itemId, amount, price, bought, slot, playerHash) VALUES (1, 1, 1, 1, 1, 1);
//Below Query Should Pass
INSERT INTO Buying(itemId, amount, price, bought, slot, playerHash) VALUES (1, 1, 1, 1, 1, 2);
//Below Query Should Fail
INSERT INTO Buying(itemId, amount, price, bought, slot, playerHash) VALUES (1, 1, 1, 1, 1, 2);
//Below Query Should Pass
INSERT INTO Buying(itemId, amount, price, bought, slot, playerHash) VALUES (1, 1, 1, 1, 0, 2);

问题当然是它们都通过并导致重复条目

目前我用的是这张表DDL

CREATE TABLE Buying ( 
    id         INTEGER PRIMARY KEY AUTOINCREMENT,
    itemId     INTEGER NOT NULL,
    amount     INTEGER NOT NULL,
    price      INTEGER NOT NULL,
    bought     INTEGER NOT NULL,
    collected  INTEGER NOT NULL
                       DEFAULT ( 0 ),
    overpaid   INTEGER NOT NULL
                       DEFAULT ( 0 ),
    slot       INTEGER NOT NULL,
    aborted    BOOLEAN NOT NULL
                       DEFAULT ( 0 ),
    playerHash INTEGER NOT NULL 
);

Answer 1

添加到你的ddl中

create table ... ( ...
...,
unique(slot, player));