diff --git a/.github/Clarian_Triggers.sql b/.github/Clarian_Triggers.sql
new file mode 100644
index 0000000..ec60266
--- /dev/null
+++ b/.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');
\ No newline at end of file
diff --git a/.github/Lab2-triggers_and_check_constraints.jpeg b/.github/Lab2-triggers_and_check_constraints.jpeg
new file mode 100644
index 0000000..5f78ce5
Binary files /dev/null and b/.github/Lab2-triggers_and_check_constraints.jpeg differ
diff --git a/075855-triggers.mysql b/075855-triggers.mysql
new file mode 100644
index 0000000..8308aed
--- /dev/null
+++ b/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;
diff --git a/075855-triggers.sql b/075855-triggers.sql
new file mode 100644
index 0000000..a33b047
--- /dev/null
+++ b/075855-triggers.sql
@@ -0,0 +1,195 @@
+-- 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;
+ 
+ -- STEP 4
+ UPDATE `employees`
+SET
+`lastName` = 'Muiruri'
+WHERE
+`employeeNumber` = '1056';
+
+UPDATE `employees`
+SET
+`email` = 'mmuiruri@classicmodelcars.com'
+WHERE
+`employeeNumber` = '1056';
+
+SELECT * FROM employees_undo;
+
+-- STEP 5
+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_reminders_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
+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
+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');
+
+DELETE FROM `customers` WHERE `customerNumber` = '497';
+
+select * from customers_data_reminders;
+
+INSERT INTO `customers`
+(`customerNumber`, `customerName`, `contactLastName`, `contactFirstName`,
+`phone`, `addressLine1`, `city`, `country`, `salesRepEmployeeNumber`)
+VALUES
+('497', 'House of Leather', 'Wambua', 'Gabriel', '+254 720 123 456', '9
+Agha Khan Walk', 'Nairobi', 'Kenya', 1401);
+
+select * from customers_data_reminders;
+
+UPDATE `customers` SET `postalCode` = '00100' WHERE `customerNumber` =
+'497';
+
+select * from customers_data_reminders;
+
+-- STEP 8
+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
+ 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 ;
+
+SHOW CREATE TABLE part;
+-- STEP 10
+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',
+'P051201576U', 'toysRus@gmail.com', '100', '100');
+
+UPDATE `part` SET `part_sellingprice` = '250.00' WHERE (`part_no` = '001');
+
+SHOW TRIGGERS;
+ 
diff --git a/170490 -triggers.mysql b/170490 -triggers.mysql
new file mode 100644
index 0000000..43e1d46
--- /dev/null
+++ b/170490 -triggers.mysql	
@@ -0,0 +1,170 @@
+-- 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');
\ No newline at end of file
diff --git a/Lab2-triggers_and_check_constraints.sql b/Lab2-triggers_and_check_constraints.sql
new file mode 100644
index 0000000..c6d8c81
--- /dev/null
+++ b/Lab2-triggers_and_check_constraints.sql
@@ -0,0 +1,96 @@
+-- switch to the current database
+USE 75855_lab2_triggers;
+
+-- STEP 1: Transaction
+
+-- turn of autocommit option
+SET autocommit = OFF;
+
+-- set isolation level
+SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
+
+START TRANSACTION;
+
+-- create the new column in orders table to record the orderTotal amount
+ALTER TABLE orders
+ADD orderTotal decimal(10,2);
+
+-- create the new column in payments table to record the ordorderNumber
+ALTER TABLE payments
+ADD orderNumber int NOT NULL;
+-- Add a check constraint to check the credit limit column in the customers table
+ALTER TABLE customers
+ADD CONSTRAINT check_credit_limit CHECK (creditLimit >= 0);
+
+-- Create Triggers
+
+-- Trigger 1: check if the customerNumber is valid
+DELIMITER //
+CREATE TRIGGER order_customer_check
+BEFORE INSERT ON orders
+FOR EACH ROW
+BEGIN 
+    -- Check if the customerNumber exists in the customers table
+    SELECT COUNT(*) INTO @customer_exists
+    FROM customers
+    WHERE customerNumber = NEW.customerNumber;
+    
+    IF @customer_exists = 0 THEN
+        SIGNAL SQLSTATE '45000'
+        SET MESSAGE_TEXT = 'Invalid customerNumber';
+    END IF;  
+   
+END;
+//
+DELIMITER ;
+
+-- Trigger 2: Check if a payment is made when an order is inserted
+DROP TRIGGER IF EXISTS order_payment_check;
+
+-- Recreate the trigger with new logic
+DELIMITER //
+CREATE TRIGGER order_payment_check
+BEFORE INSERT ON payments
+FOR EACH ROW
+BEGIN
+    DECLARE order_amount DECIMAL(10, 2);
+    
+    -- Get the total amount of the corresponding order
+    SELECT orderTotal INTO order_amount
+    FROM orders
+    WHERE orderNumber = NEW.orderNumber;
+
+    -- Check if the payment amount is less than the order amount
+    IF NEW.amount < order_amount THEN
+        SIGNAL SQLSTATE '45000'
+        SET MESSAGE_TEXT = 'Payment amount is less than the order amount';
+    END IF;
+END;
+//
+DELIMITER ;
+
+-- Create a save point before an order is made
+SAVEPOINT order_savepoint;
+
+-- Insert a new order
+SELECT @orderNumber := MAX(orderNumber)+1 FROM orders;
+INSERT INTO orders (orderNumber,orderDate, requiredDate, shippedDate, status, comments, customerNumber, orderTotal)
+VALUES (@orderNumber,DATE(NOW()), DATE(DATE_ADD(NOW(), INTERVAL 3 DAY)), NULL, 'Processing', 'New order', 103, 1500);
+
+select * from orders order by orderNumber desc;
+
+select * from payments order by customerNumber asc;
+
+-- Create a save point before a payment is made
+SAVEPOINT payment_savepoint;
+
+-- Record a payment for the order
+INSERT INTO payments (customerNumber, checkNumber, paymentDate, amount, orderNumber)
+VALUES (103, 'CHK123456', DATE(NOW()), 1200, @orderNumber);
+
+-- Commit the transaction
+COMMIT;
+
+SET autocommit = ON;
+
+
diff --git a/README.md b/README.md
index cb21b12..9ac4bee 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,4 @@
+[![Review Assignment Due Date](https://classroom.github.com/assets/deadline-readme-button-24ddc0f5d75046c5622901739e7c5dd533143b0c8e959d652212380cedb1ea36.svg)](https://classroom.github.com/a/8egdwdH8)
 [![Open in Visual Studio Code](https://classroom.github.com/assets/open-in-vscode-718a45dd9cf7e7f842a935f5ebbe5719a5e09af4491e668f4dbf3b35d5cca122.svg)](https://classroom.github.com/online_ide?assignment_repo_id=12109866&assignment_repo_type=AssignmentRepo)
 # Required Lab Work Submission
 Please refer to the lab manual (Lab 2 on transactions and check constraints) available here for the detailed instructions: [https://elearning.strathmore.edu/course/view.php?id=3277](https://elearning.strathmore.edu/course/view.php?id=3277)
diff --git a/makhatsa.mysql b/makhatsa.mysql
new file mode 100644
index 0000000..f8d3c98
--- /dev/null
+++ b/makhatsa.mysql
@@ -0,0 +1,2 @@
+----to list database
+show DATABASES;
\ No newline at end of file