Consider the following schema

Highschooler $($ID int, name text, grade int$)$;

Write a trigger that automatically deletes students when they graduate, i$.$e$.,$ when their grade is updated to exceed $12.$

$2.$ Consider the following relational schema:

PRODUCT $($ProductCode$,$ Name, Type$)$

TRANSACTION $($TransCode$,$ SellerCode, BuyerCode, TitleCode, Quantity, Value, Date, Instant$)$

OPERATOR $($Code$,$ Name, Address, Availability$)$

Build a trigger system that keeps the value of Availability of Operator updated after insertion of tuples in Transaction, taking

into account that for each transaction in which the operator sells, the amount of the transaction must be added to its

availability and subtracted for purchases.

$3.$ Consider the following relational schema that manages the assignment of scholarships to students

APPLICATION $($StudentID$,$ Date, State$)$

COURSE $($CourseID$,$ Title, Credits$)$

RANKING $($StudentID$,$ Average, Credits, Rank$)$

EXAM $($CourseID$,$ StudentID, Date, Grade$)$

We want to manage through a system of triggers the assignment of scholarships to students. The scholarships are awarded

to students who apply and, at the date of the application, have taken exams for at least $50$ credits, with an average score of

at least $27.$

$$ If the requirements are not met, the application is automatically rejected; otherwise accepted. In both cases, the

value of the column State in APPLICATION is changed $($initially it was NULL$),$ respectively, with "rejected" or

"accepted".