SQLite唯一键与两列的组合 [英] SQLite Unique Key with a combination of two columns
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问题描述
我想确保当我运行以下查询只有第一个 INSERT INTO
将工作..我知道我必须使
UNIQUE
I'm trying to make sure when I run the following query only the first INSERT INTO
will work.. I know I have to make slot
UNIQUE
插槽可以是0-5 INTEGER,
The slot could be from 0-5 INTEGER but it doesn't mean that only 6 table data rows could be accepted into that table.
对于与之匹配的每个playerHash,只允许6个表数据行作为
For each playerHash that matches it should only allow 6 table data rows as slot
is UNIQUE
(cannot have duplicate of same slot column, for each playerHash column).
//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);
问题当然是他们都通过并导致重复条目
Problem of course is they all pass and cause duplicate entries
目前我使用这个表DDL
Currently I use this table 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
);
推荐答案
添加到您的ddl
create table ... ( ...
...,
unique(slot, player));
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