級聯刪除mysql

Question

我正在創建一個小型的3表數據庫，基本上使用它作爲數據的緩衝區，所以它使用的是ENGINER = MEMORY。該數據庫具有以下結構：

我沒有那麼多到MySQL，所以我的問題是：是否有可能有級聯刪除，這樣，當我刪除MeassurementIteration，所有MeassurementSet的和與迭代相關的度量將被刪除？

代碼：

-- Last modification date: 2017-04-03 08:09:06.263 

-- tables 
-- Table: Meassurement 
CREATE TABLE Meassurement (
    id int NOT NULL AUTO_INCREMENT, 
    msWay varchar(75) NOT NULL, 
    qosClass int NOT NULL, 
    timeReceived timestamp NOT NULL, 
    timeReceivedFarEnd timestamp NOT NULL, 
    timeSent timestamp NOT NULL, 
    timeSentFarEnd timestamp NULL, 
    seq int NOT NULL, 
    MeassurementSet_id int NOT NULL, 
    CONSTRAINT Meassurement_pk PRIMARY KEY (id) 
) ENGINE MEMORY COMMENT 'Contains data for a single meassurement'; 

-- Table: MeassurementIteration 
CREATE TABLE MeassurementIteration (
    id int NOT NULL AUTO_INCREMENT, 
    start timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, 
    end timestamp NULL, 
    active bool NOT NULL, 
    CONSTRAINT MeassurementIteration_pk PRIMARY KEY (id) 
); 

-- Table: MeassurementSet 
CREATE TABLE MeassurementSet (
    id int NOT NULL AUTO_INCREMENT, 
    avgDelayRT double NULL, 
    avgDelayTR double NULL, 
    avgRTD double NULL, 
    maxDelayRT double NULL, 
    maxDelayTR double NULL, 
    maxRTD double NULL, 
    minRTD double NULL, 
    minDelayRT double NULL, 
    minDelayTR double NULL, 
    qosClass int NOT NULL, 
    stdDev double NULL, 
    stdDevRT double NULL, 
    stdDevTR double NULL, 
    msWay varchar(75) NOT NULL, 
    MeassurementIteration_id int NOT NULL, 
    CONSTRAINT MeassurementSet_pk PRIMARY KEY (id) 
) ENGINE MEMORY COMMENT 'Contains a set of meassurements specific to a qosclass and Meassurementway'; 

-- foreign keys 
-- Reference: MeassurementSet_MeassurementIteration (table: MeassurementSet) 
ALTER TABLE MeassurementSet 
    ADD CONSTRAINT MeassurementSet_MeassurementIteration 
    FOREIGN KEY MeassurementSet_MeassurementIteration (MeassurementIteration_id) 
     REFERENCES MeassurementIteration (id) ON DELETE CASCADE; 

-- Reference: Meassurement_MeassurementSet (table: Meassurement) 
ALTER TABLE Meassurement 
    ADD CONSTRAINT Meassurement_MeassurementSet 
    FOREIGN KEY Meassurement_MeassurementSet (MeassurementSet_id) 
     REFERENCES MeassurementSet (id) ON DELETE CASCADE; 

-- End of file. 

最好的問候。

Answer 1

您不能使用ON DELETE CASCADE和ENGINE = MEMORY。 外鍵不受支持。

這裏的參考：（MySQL的文件）[https://dev.mysql.com/doc/refman/5.6/en/memory-storage-engine.html]

Table 15.4 MEMORY Storage Engine Features 
--------------------------------------------------- 
Foreign key support No 

您可以檢查此也，另一個相似的問題。 MySql memory engine do not check on update foreign key?

Answer 2

SELECT table_nameenter代碼在這裏 FROM referential_constraints WHERE constraint_schema = 'classicmodels' enter code here和 referenced_table_name = '建築' AND DELETE_RULE = 'CASCADE'