MySQL Relation CasCade On Delete/On Update

CREATE TABLE `customer` (
  `CustomerID` varchar(4) NOT NULL,
  `Name` varchar(50) NOT NULL,
  `Email` varchar(50) NOT NULL,
  `CountryCode` varchar(2) NOT NULL,
  `Budget` double NOT NULL,
  `Used` double NOT NULL,
  PRIMARY KEY  (`CustomerID`)
) ENGINE=InnoDB;


INSERT INTO `customer` VALUES ('C001', 'Win Weerachai', '[email protected]', 'TH', 1000000, 600000);
INSERT INTO `customer` VALUES ('C002', 'John  Smith', '[email protected]', 'EN', 2000000, 800000);
INSERT INTO `customer` VALUES ('C003', 'Jame Born', '[email protected]', 'US', 3000000, 600000);
INSERT INTO `customer` VALUES ('C004', 'Chalee Angel', '[email protected]', 'US', 4000000, 100000);
INSERT INTO `customer` VALUES ('C005', 'Weerachai Nukitram', '[email protected]', 'TH', 2000000, 100000);

CREATE TABLE `audit` (
  `AuditID` int(4) NOT NULL,
  `CustomerID` varchar(4) NOT NULL,
  `Date` date NOT NULL,
  `Used` double NOT NULL,
  PRIMARY KEY  (`AuditID`),
  FOREIGN KEY (CustomerID) REFERENCES customer (CustomerID) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB;


INSERT INTO `audit` VALUES (1, 'C001', '2008-08-01', 100000);
INSERT INTO `audit` VALUES (2, 'C001', '2008-08-05', 200000);
INSERT INTO `audit` VALUES (3, 'C001', '2008-08-10', 300000);
INSERT INTO `audit` VALUES (4, 'C002', '2008-08-02', 400000);
INSERT INTO `audit` VALUES (5, 'C002', '2008-08-07', 100000);
INSERT INTO `audit` VALUES (6, 'C002', '2008-08-15', 300000);
INSERT INTO `audit` VALUES (7, 'C003', '2008-08-20', 400000);
INSERT INTO `audit` VALUES (8, 'C003', '2008-08-25', 200000);
INSERT INTO `audit` VALUES (9, 'C004', '2008-07-04', 100000);
INSERT INTO `audit` VALUES (10, 'C005', '2008-07-04', 200000);