Topic 8. Object-relational mapping with Entity Framework Core

Goal: become familiar with the principles of object-relational mapping and the Entity Framework Core library; learn to describe a data model with conventions, annotations, and the Fluent API, and to create and apply migrations to a PostgreSQL database; master LINQ to Entities queries with projections, grouping, and pagination, loading related data, change tracking, transactions, and using the context in a Windows Forms application.

Lecture contents

1. The data context and model — ORM and Entity Framework Core · Installation and the data context · The model: conventions, annotations, and the Fluent API · Relationships between entities
2. Migrations and LINQ queries — Migrations · LINQ to Entities queries
3. Related data and change tracking — Loading related data · Change tracking
4. Transactions, raw SQL, and testing — Transactions and concurrency · Raw SQL, context lifetime, and testing
5. Common mistakes — Common mistakes

Practice and review

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