问MySql内存引擎不检查更新外键？

EN

CREATE TABLE testInnoDb1 (
    c1 int(11) PRIMARY KEY
) ENGINE=InnoDB;

CREATE TABLE testInnoDb2 (
    c1 int(11) PRIMARY KEY,
    FOREIGN KEY (c1) REFERENCES testInnoDb1(c1) ON UPDATE CASCADE ON DELETE CASCADE
) ENGINE=InnoDB;

INSERT INTO testInnoDb1 (c1) VALUES (42);
INSERT INTO testInnoDb2 (c1) VALUES (42);
-- INSERT INTO testInnoDb2 (c1) VALUES (64); -- This will fail
-- UPDATE testInnoDb2 SET c1=128; -- This will fail

CREATE TABLE testMem1 (
    c1 int(11) PRIMARY KEY
) ENGINE=MEMORY;

CREATE TABLE testMem2 (
    c1 int(11) PRIMARY KEY,
    FOREIGN KEY (c1) REFERENCES testMem1(c1) ON UPDATE CASCADE ON DELETE CASCADE
) ENGINE=MEMORY;

INSERT INTO testMem1 (c1) VALUES (42);
INSERT INTO testMem2 (c1) VALUES (42);
-- INSERT INTO test2 (c1) VALUES (64); -- This will fail
UPDATE testMem2 SET c1=128; -- This should fail?