MYSQL錯誤：錯誤1215：無法添加外鍵約束

Question

我試圖轉發工程我的ERD工作臺6.0中的計劃，但我得到這個錯誤。我檢查過所有列類型，它們是一樣的。我在這裏查看了類似的問題，但仍然找不到答案。這裏的錯誤日誌：

xecuting SQL script in server 

ERROR: Error 1215: Cannot add foreign key constraint 







-- ----------------------------------------------------- 

-- Table `proj`.`employee` 

-- ----------------------------------------------------- 

CREATE TABLE IF NOT EXISTS `proj`.`employee` (

    `employee_id` INT NOT NULL, 

    `position_id` INT NOT NULL, 

    PRIMARY KEY (`employee_id`), 

    CONSTRAINT `fk_employee_employee_history1` 

    FOREIGN KEY (`employee_id`) 

    REFERENCES `proj`.`employee_history` (`employee_id`) 

    ON DELETE NO ACTION 

    ON UPDATE NO ACTION, 

    CONSTRAINT `fk_employee_equipment_rentals1` 

    FOREIGN KEY (`employee_id`) 

    REFERENCES `proj`.`equipment_rentals` (`handling_employee_id`) 

    ON DELETE NO ACTION 

    ON UPDATE NO ACTION, 

    CONSTRAINT `fk_employee_scheduled_trips1` 

    FOREIGN KEY (`employee_id`) 

    REFERENCES `proj`.`scheduled_trips` (`leader`) 

    ON DELETE NO ACTION 

    ON UPDATE NO ACTION, 

    CONSTRAINT `fk_employee_scheduled_trips2` 

    FOREIGN KEY (`employee_id`) 

    REFERENCES `proj`.`scheduled_trips` (`assistant`) 

    ON DELETE NO ACTION 

    ON UPDATE NO ACTION) 

ENGINE = InnoDB 



SQL script execution finished: statements: 8 succeeded, 1 failed 



Fetching back view definitions in final form. 

Nothing to fetch 

Answer 1

所以事實證明，我的外鍵約束都搞砸了。我有關係倒退。我沒有使用外鍵引用主鍵，而是讓主鍵BE成爲引用非唯一列的外鍵。我扭轉了這一點，並且它工作。