It is usual to control access to the data via the front end application, for example by displaying data as ‘read only'. This part of the assignment illustrates how programmers can create reusable (and therefore shareable) code, you will be creating simple components to reuse and call from elsewhere in your code.
For the case study:
a) Identify and create a user defined function.
b) Identify a useful persistent package variable for the system.
c) Identify suitable package for the system that implements constraints. Create the package program.
d) Implement a DML type program unit (e.g. a procedure that updates data in a table) that calls the package you created in task c).
e) Implement a trigger that calls the program unit you created in task d).