Topic 15. Model/View architecture, dialogs, and database access in PySide6 applications

Goal: master standard and custom Qt models, editing through delegates and dialogs, filtering, and safely saving data in SQLite; learn to verify that the model and the database are consistent.

Lecture contents

1. Models, indexes, and roles — Why data should not live only in cells · Standard models, indexes, and roles · A custom model: the contract with the view
2. Proxies, sorting, and delegates — Proxies, sorting, and selection · Delegates: the editor is not the data source
3. Custom dialogs — Custom dialogs and their results
4. Qt SQL, repositories, and settings — Qt SQL and saving changes · A custom repository as an alternative approach · Settings, CSV, and testing · Common mistakes

Practice and review

• Practice — 3 worked examples with complete code
• Tasks — 30 variants, each with tasks at three difficulty levels
• Summary — conclusions, self-check questions, and useful links