I’m building a Windows-friendly desktop application in Python that streamlines day-to-day operations for a small trading company. The interface must be written with Tkinter, bundled through PyInstaller, and backed by a MySQL database accessed via clean helper utilities so it can be deployed quickly on any office PC. Core modules The inventory module has to keep live Stock tracking and let me see full Supplier details right next to each SKU. For billing I only need robust Payment tracking; no automated invoice runs or dunning logic for now, but each payment record must be linkable to its corresponding sale so I can reconcile quickly. Supplier management should store Contact information, a full Order history, and all relevant Contract details so my purchasing staff have everything in one place. An employee section (add / edit / deactivate) rounds out the basic HR needs. Security & data layer User passwords are to be hashed with PBKDF2. If the database still contains legacy plaintext credentials, the first successful login should migrate them automatically to hashed values. Please include a simple migration utility and clear comments around the crypto parameters (iterations, salt length). All database access should go through parameterised queries or an ORM-style helper that prevents SQL injection, and a small versioned migration script is required so I can evolve the schema later without data loss. Documents & output Invoices need to be exported as well-formatted PDFs using ReportLab. I will supply a logo; you handle layout and field mapping. Generated documents should be stored in an “Invoices” folder with an incremental naming convention. Packaging A working .spec file (or build script) for PyInstaller is mandatory so the whole program compiles into a single-folder distribution for Windows 10 and 11. Deliverables • Full Python source, organised by module • SQL schema, seed data, and migration helper • ReportLab template for the invoice PDF • PyInstaller .spec / build script and brief README • One-page quick-start guide so my in-house tech can install, create the DB, and run the app Acceptance criteria I will spin up a fresh MySQL instance, run your migration script, launch the packaged EXE, and confirm that I can: 1. Add a new product, adjust its stock, and see the change reflected instantly. 2. Enter a supplier, place an order, and have that order stored under the supplier’s history. 3. Record a sale and its payment, then print the corresponding invoice to PDF. 4. Log in with a legacy plaintext user and watch the account convert to PBKDF2 seamlessly. If everything above works smoothly and the codebase is readable with clear comments, the project is complete.