answer all Please answer 4 questions.

Use the following relational schema write functions, procedures and triggers in PL/SQL: Student (studid, FirstName, LastName, Email, phoneNumber, DateofBirth, GPA) Club (clubid, ClubName, \# studid) MemberOf (\#clubid, \#studid, joiningDate ) Activities (actid, actdt, place, durationNbHour) Organize (\#actid, \#clubid , fee) 1. Write a function called 'Checkavailability' that accepts a date and check whether 'Salalah Hall' is busy or not on that date. [5 marks] 2. Write a function called 'CheckStudentClub' that accepts a student id and returns the name of the club in which the student is participating. [5 marks] 3. Write a procedure called 'MainProc' to call the functions 'Checkavailability' and 'CheckStudentClub'. This procedure should display the appropriate messages according to the values returned by the each of the called functions (For example: If the first function returns true, the procedure will display 'Salalah Hall is free on date \#\#\#\#\#\#' otherwise 'Salalah Hall is busy on date \#\#\#\#\#\#').[5 marks] 4. Write a Trigger that stores the old data of Activities table in Activity_backup after every update or delete executed on Activities table. [5 marks] Activity_backup (Actid, Actdt, Place, timeStart, durationNbHour, Operation_date)