src/com.example.portfolio2/com/example/portfolio2/Model.java



package com.example.portfolio2;

import java.util.ArrayList;

class Model{ // The model handles all interactions with the database
    MyDB db=new MyDB();
    Model(){}
    void initialize() { // When running the program, it clears the participation database
        clearParticipation();
    }
    int getActivityIndeks(String name) { // Returns the integer value of the activity's index
        if(name ==null) return -1;
        ArrayList<String> result = db.query("select indeks from activity a where name is '"+name+"';", "indeks");
        return Integer.parseInt(result.getFirst());

    }
    void addParticipation(int activityIndex) { // Inserts the given activity into participation using the activity's index
        db.cmd("insert into participation values(123, "+activityIndex+");");
    }
    ArrayList<String> getParticipation(String program) { // Returns all activity names from activities currently in participation
        return db.query("select name from participation p inner join activity a on p.indeks = a.indeks where program is '" + program + "';", "name");
    }
    void clearParticipation() { // Removes all entries in the participation database
        db.cmd("delete from participation");
    }
    ArrayList<String> selectProgram(String program) { // Returns an arraylist of activities within the given program
        return db.query("select name from activity where program is '" + program + "';", "name");
    }
    String getSumEcts(String program){ // Returns the sum of ECTS points under the given category from the student as a string
        if(program==null)return "0";
        ArrayList<String> result = db.query("select sum(activity.ects) as total_ects,student.name from student left outer join participation on student.studid = participation.studid inner join activity on participation.indeks = activity.indeks where program is '"+program+"' group by student.studid ;", "total_ects");
        if (result.isEmpty()) return "0";
        return result.getFirst();
    }
    ArrayList<String> getAllActivities() {
        return db.query("select name from activity;", "name");
    }
}