Read the examples about procedures and transactions from here

1. Make a Stored Procedure named addHours. That procedure should add a given amount of hours to given person(id_person) to given project (id_project). So, you should be able to call it like this:
   CALL addHours(x, y, z).
   Where
   • x is the id_person
   • y is the id_project
   • z is the amount of hours
   You can test your procedure with below values
   • CALL addHours(9999,101,500); -> should not success
   • CALL addHours(201,101,500); -> should success
   • CALL addHours(201,105,500); -> should success
2. Make a Stored Procedure named addHoursNew. That procedure should work in the same ways as addHours, but if the x and y already exists in the hour-table, it will add the amount to the existing amount.
   In order to test the procedure, execute first this command:
   DELETE FROM hour where id_project='105';
   And then execute several times CALL addHoursNew(201,'105',500);

1. Read the about triggers from this page
2. Create table named person_log which has fields:
   • id_personLog INT PRIMARY KEY AUTO_INCREMENT
   • Explanation VARCHAR(255)
   • Logtime DATETIME
3. Create trigger which will add Text "Person updated" and Date of today to the table person_log, if you update person data