ExamTracker

A desktop app for Greek tutoring schools (φροντιστήρια). A teacher logs in, then tracks student exam marks and tuition payments from a single Tkinter window. The interface is entirely in Greek.

Stack

• Python 3 with Tkinter/ttk for the GUI
• PostgreSQL via psycopg2 for storage
• python-dotenv for reading the database connection string from a .env file

No web server, no ORM. app.py calls straight into db_comms.py, which runs raw SQL against five tables.

Features

The sidebar has four sections:

• Στατιστικά (Statistics): search a student and pull their overall average, their average in one subject, or a table of every mark they've logged for a subject.
• Καταχώρηση (Exam entry): log a mock exam with student name, subject, date, and mark.
• Πληρωμές (Payments): log a tuition payment and look up a student's balance. The balance comes from monthly_fee × months_since_enrollment − total_paid. The app looks up the monthly fee by the student's class in the grade table and counts months from the enrollment date to the current month. A payment history table sits below the search.
• Νέος Μαθητής (New student): register a student with name, age, class, and enrollment date.

Login checks a username/password pair against the users table. Passwords are hashed client-side with SHA-256 before the query runs; there's no salting or hashing on the server side beyond that.

Project layout

examtracker.gr/
├── app.py                     # Tkinter GUI: login, navigation, all four pages
├── db_comms.py                # DB layer: Student, mock_exam, payment, Backend_user
├── requirements.txt
├── setup/
│   ├── .env.example           # Template for DATABASE_URL
│   └── initial_commands.sql   # Creates the five tables
├── demo_app/
│   ├── app_demo.py            # Same GUI, imports db_comms_demo instead of db_comms
│   └── db_comms_demo.py       # In-memory backend, no database required
├── images/                    # Logo
└── info/                      # Design scratch files (isolated GUI prototype, drawio diagram)

Database

Five tables, created by setup/initial_commands.sql:

Table	Purpose
students	name, date-of-birth field (repurposed to store age; see note below), class, enrollment date
exams	one row per mock exam mark: student, subject, date, mark
payments	one row per tuition payment: student, amount, date
grade	one row per class name, holding its monthly fee and an active flag
users	login credentials

Everything is keyed on student name (uppercased on write and on lookup) rather than a foreign key to students.id. There's no seed data for grade in initial_commands.sql, so a fresh database needs rows added there before balances can resolve.

One deliberate schema shortcut: the students.dob column is NOT NULL but the UI has no date-of-birth field, so Student.save() writes the student's age into it as a string instead.

Running it

With a real database

1. pip install -r requirements.txt
2. Create a PostgreSQL database and run setup/initial_commands.sql against it.
3. Copy setup/.env.example to .env and set DATABASE_URL to your connection string.
4. Add at least one row to users (with a SHA-256 password hash) and one row per class to grade.
5. python app.py

Demo mode, no database

python demo_app/app_demo.py

Login with demo / demo123. db_comms_demo.py swaps every SQL call for lookups against in-memory Python dicts and lists, pre-populated with three sample students, some exam marks, payments, and per-class fees. Nothing persists between runs.

Notes on info/

info/isolated_gui.py strips things down further: same visual layout as app.py, but every button handler returns a canned status message. It has no db_comms import, no real or fake data store, nothing wired up. It reads as a UI-only prototype kept for reference. class_view.drawio diagrams the class structure. error_codes.md and setup.md sit empty.