When will you use this?

Use EF Core when your app stores data in SQL Server, PostgreSQL, or SQLite.

• Orders, customers, and products live in SQL Server — EF Core reads and writes them with C#.
• Migrations let teams update database schema without manual SQL scripts in production.

Real-world: Practo-style clinic API

The Healthcare team building Practo-style clinic API uses Relationships in EF Core to link Order to Customer and OrderLine to Product correctly. patients and doctors never see the C# code — they just get a fast, reliable appointment booking and slots.

Production-style code

public class ShopDbContext : DbContext
{
    public ShopDbContext(DbContextOptions<ShopDbContext> options) : base(options) { }
    // DbSet properties for Relationships in EF Core
}

What happens in production: In Practo-style clinic API, getting Relationships in EF Core right means patients and doctors trust the appointment booking and slots every day.

Lesson example (start here)

Copy this smaller example first. Once it works, compare it with the real-world code above.

public class ShopDbContext : DbContext
{
    public ShopDbContext(DbContextOptions<ShopDbContext> options) : base(options) { }
    // DbSet properties for Relationships in EF Core
}

Line-by-line walkthrough

How it works (big picture)

• Study the example line by line.
• Each part connects to Relationships in EF Core.
• Edit one line, save, run dotnet run, and see what changes.

Do this on your computer

1. Update ShopDbContext or your entity classes.
2. Create or apply a migration if the schema changed.
3. Query or save data and verify in SSMS or Azure Data Studio.
4. Read the real-world section and name which part of the app uses this topic.
5. Run the example locally with dotnet run and confirm the same behavior.
6. Change one value in the example (route, text, or connection string) and predict what will happen before you save.

Experiments — try changing this

• Change a string or route in the example and save — watch the browser or Swagger response update.
• Break the code on purpose (remove a semicolon), read the error message, then fix it.
• Add one more property to the entity class and create a migration.
• Use dotnet watch run while editing Relationships in EF Core — the app restarts on save.

Remember

You learned what Relationships in EF Core is and when to use it in ShopNest. Practice by changing the example yourself. Use the Next link when you can explain it in your own words.

Common questions