Qt lab — shapes canvas with SQLite persistence. Two implementations (lab92, lab99).
lab92 — QGraphicsScene + custom ShapeModel. Each shape (ellipse, rectangle, polygon) is stored in an SQLite database via QSqlTableModel. Shapes can be connected with lines. Deleting a shape also removes all its connections from the DB.
lab99 — extends lab92 with a QTableView panel filtered by shape type and a custom IconDelegate: cells render 1 icon if count 1–3, 2 icons if 4–10, 3 icons if > 10 for that shape type. Shapes can be hidden from the view without deleting them from the DB.
DB columns: shape ID, shape type, linked shape IDs, total count of that type.