Feedback

.github/Clarian_Triggers.sql

@@ -0,0 +1,171 @@
+-- List all the databases
+SHOW DATABASES;
+-- switch to the current database
+USE 75855_lab2_triggers;
+-- list of all tables
+SHOW TABLES;
+
+-- STEP 1
+SHOW CREATE TABLE employees;
+CREATE TABLE `employees` (
+  `employeeNumber` int NOT NULL,
+  `lastName` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `firstName` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `extension` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `email` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `officeCode` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `reportsTo` int DEFAULT NULL,
+  `jobTitle` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  PRIMARY KEY (`employeeNumber`),
+  KEY `reportsTo` (`reportsTo`),
+  KEY `officeCode` (`officeCode`),
+  CONSTRAINT `employees_ibfk_1` FOREIGN KEY (`reportsTo`) REFERENCES `employees` (`employeeNumber`),
+  CONSTRAINT `employees_ibfk_2` FOREIGN KEY (`officeCode`) REFERENCES `offices` (`officeCode`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
+
+CREATE TABLE `employees_undo` (
+  `date_of_change` timestamp(2) NOT NULL DEFAULT CURRENT_TIMESTAMP(2),
+  `employeeNumber` int NOT NULL,
+  `lastName` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `firstName` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `extension` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `email` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `officeCode` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `reportsTo` int DEFAULT NULL,
+  `jobTitle` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `change_type` varchar(50) NOT NULL,
+  PRIMARY KEY (`date_of_change`),
+  UNIQUE KEY `date_of_change_UNIQUE` (`date_of_change`)
+
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
+
+-- STEP 2
+CREATE
+
+ TRIGGER TRG_BEFORE_UPDATE_ON_employees
+ BEFORE UPDATE ON employees FOR EACH ROW
+
+ INSERT INTO `employees_undo` SET
+ `date_of_change` = CURRENT_TIMESTAMP(2),
+ `employeeNumber` = OLD.`employeeNumber` ,
+ `lastName` = OLD.`lastName` ,
+ `firstName` = OLD.`firstName` ,
+ `extension` = OLD.`extension` ,
+ `email` = OLD.`email` ,
+ `officeCode` = OLD.`officeCode` ,
+ `reportsTo` = OLD.`reportsTo` ,
+ `jobTitle` = OLD.`jobTitle` ,
+ `change_type` = 'An update DML operation was executed';
+
+ -- STEP 4
+ SHOW TRIGGERS;
+ UPDATE `employees`
+SET
+`lastName` = 'Muiruri'
+WHERE
+
+`employeeNumber` = '1056';
+SELECT * FROM employees_undo;
+
+-- STEP 5 Create a table to store reminders
+CREATE TABLE `customers_data_reminders` (
+`customerNumber` int NOT NULL COMMENT 'Identifies the customer whose data
+is partly missing',
+`customers_data_reminders_timestamp` timestamp(2) NOT NULL DEFAULT
+CURRENT_TIMESTAMP(2) COMMENT 'Records the time when the missing data was
+detected',
+`customers_data_reminders_message` varchar(100) NOT NULL COMMENT 'Records
+a message that helps the customer service personnel to know what data is
+missing from the customer\'s record',
+`customers_data_reminders_status` tinyint NOT NULL DEFAULT '0' COMMENT
+'Used to record the status of a reminder (0 if it has not yet been
+addressed and 1 if it has been addressed)',
+PRIMARY KEY
+(`customerNumber`,`customers_data_reminders_timestamp`,`customers_data_remi
+nders_message`,`customers_data_reminders_status`),
+CONSTRAINT `FK_1_customers_TO_M_customers_data_reminders` FOREIGN KEY
+(`customerNumber`) REFERENCES `customers` (`customerNumber`)
+ON DELETE CASCADE
+ON UPDATE CASCADE
+) ENGINE=InnoDB COMMENT='Used to remind the customer service personnel
+about a client\'s missing data. This enables them to ask the client to
+provide the data during the next interaction with the client.'
+
+-- STEP 6 Create a trigger that has multiple statements
+DELIMITER $$
+CREATE TRIGGER TRG_AFTER_INSERT_ON_customers
+AFTER INSERT ON customers FOR EACH ROW
+BEGIN
+IF NEW.postalCode IS NULL THEN
+INSERT INTO `customers_data_reminders`
+(`customerNumber`, `customers_data_reminders_timestamp`,
+`customers_data_reminders_message`)
+VALUES (NEW.customerNumber, CURRENT_TIMESTAMP(2), 'Please remember
+to record the client\'s postal code');
+END IF;
+IF NEW.salesRepEmployeeNumber IS NULL THEN
+INSERT INTO `customers_data_reminders`
+(`customerNumber`, `customers_data_reminders_timestamp`,
+`customers_data_reminders_message`)
+VALUES (NEW.customerNumber, CURRENT_TIMESTAMP(2), 'Please remember
+to assign a sales representative to the client');
+END IF;
+IF NEW.creditLimit IS NULL THEN
+INSERT INTO `customers_data_reminders`
+(`customerNumber`, `customers_data_reminders_timestamp`,
+`customers_data_reminders_message`)
+VALUES (NEW.customerNumber, CURRENT_TIMESTAMP(2), 'Please remember
+to set the client\'s credit limit');
+END IF;
+END$$
+DELIMITER ;
+
+-- STEP 7 Confirm the trigger is fired when insertion is made
+INSERT INTO `customers`
+(`customerNumber`, `customerName`, `contactLastName`, `contactFirstName`,
+`phone`, `addressLine1`, `city`, `country`)
+VALUES
+('497', 'House of Leather', 'Wambua', 'Gabriel', '+254 720 123 456', '9
+Agha Khan Walk', 'Nairobi', 'Kenya');
+
+-- STEP 8 Create a new table to store parts data
+CREATE TABLE part (
+part_no VARCHAR(18) PRIMARY KEY,
+part_description VARCHAR(255),
+part_supplier_tax_PIN VARCHAR (11) CHECK (part_supplier_tax_PIN REGEXP
+'^[A-Z]{1}[0-9]{9}[A-Z]{1}$'),
+part_supplier_email VARCHAR (55),
+part_buyingprice DECIMAL(10,2 ) NOT NULL CHECK (part_buyingprice >= 0),
+part_sellingprice DECIMAL(10,2) NOT NULL,
+CONSTRAINT CHK_part_sellingprice_GT_buyingprice CHECK
+(part_sellingprice >= part_buyingprice),
+CONSTRAINT CHK_part_valid_supplier_email CHECK (part_supplier_email
+REGEXP '^[a-zA-Z0-9]{3,}@[a-zA-Z0-9]{1,}\\.[a-zA-Z0-9.]{1,}$')
+);
+
+-- STEP 9. Create the following user-defined error in a trigger
+DELIMITER //
+CREATE TRIGGER TRG_BEFORE_UPDATE_ON_part
+BEFORE UPDATE ON part FOR EACH ROW
+BEGIN
+DECLARE errorMessage VARCHAR(255);
+DECLARE EXIT HANDLER FOR SQLSTATE '45000'
+BEGIN
+RESIGNAL SET MESSAGE_TEXT = errorMessage;
+END;
+SET errorMessage = CONCAT('The new selling price of ',
+NEW.part_sellingprice, ' cannot be 2 times greater than the current selling
+price of ', OLD.part_sellingprice);
+IF NEW.part_sellingprice > OLD.part_sellingprice * 2 THEN
+SIGNAL SQLSTATE '45000';
+END IF;
+END//
+DELIMITER ;
+
+
+-- STEP 10. Confirm that the static, dynamic, and semantic constraints are working
+
+INSERT INTO `part` (`part_no`, `part_description`, `part_supplier_tax_PIN`,
+`part_supplier_email`, `part_buyingprice`, `part_sellingprice`)
+VALUES ('001', 'The tyres of a 1958 Chevy Corvette Limited Edition',
+'P05120157U', 'toysRus@gmail', '100', '50');

075855-triggers.mysql

@@ -0,0 +1,61 @@
+-- List all the databases
+SHOW DATABASES;
+-- switch to the current database
+USE 75855_lab2_triggers;
+-- list of all tables
+SHOW TABLES;
+
+-- STEP 1
+SHOW CREATE TABLE employees;
+CREATE TABLE `employees` (
+  `employeeNumber` int NOT NULL,
+  `lastName` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `firstName` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `extension` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `email` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `officeCode` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `reportsTo` int DEFAULT NULL,
+  `jobTitle` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  PRIMARY KEY (`employeeNumber`),
+  KEY `reportsTo` (`reportsTo`),
+  KEY `officeCode` (`officeCode`),
+  CONSTRAINT `employees_ibfk_1` FOREIGN KEY (`reportsTo`) REFERENCES `employees` (`employeeNumber`),
+  CONSTRAINT `employees_ibfk_2` FOREIGN KEY (`officeCode`) REFERENCES `offices` (`officeCode`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
+
+CREATE TABLE `employees_undo` (
+  `date_of_change` timestamp(2) NOT NULL DEFAULT CURRENT_TIMESTAMP(2),
+  `employeeNumber` int NOT NULL,
+  `lastName` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `firstName` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `extension` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `email` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `officeCode` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `reportsTo` int DEFAULT NULL,
+  `jobTitle` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
+  `change_type` varchar(50) NOT NULL,
+  PRIMARY KEY (`date_of_change`),
+  UNIQUE KEY `date_of_change_UNIQUE` (`date_of_change`)
+
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
+
+-- STEP 2
+CREATE
+
+ TRIGGER TRG_BEFORE_UPDATE_ON_employees
+ BEFORE UPDATE ON employees FOR EACH ROW
+
+ INSERT INTO `employees_undo` SET
+ `date_of_change` = CURRENT_TIMESTAMP(2),
+ `employeeNumber` = OLD.`employeeNumber` ,
+ `lastName` = OLD.`lastName` ,
+ `firstName` = OLD.`firstName` ,
+ `extension` = OLD.`extension` ,
+ `email` = OLD.`email` ,
+ `officeCode` = OLD.`officeCode` ,
+ `reportsTo` = OLD.`reportsTo` ,
+ `jobTitle` = OLD.`jobTitle` ,
+ `change_type` = 'An update DML operation was executed';
+
+ -- STEP 3
+ SHOW TRIGGERS;