From LINQ to durable data

SQL & Entity Framework

See how EF Core models, translates, tracks, and saves data—and how SQL keys, indexes, and transactions keep the database useful and correct.

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Explore the concepts

Pick a concept. Read the code. Make the call.

Each example contrasts a common design problem with one possible improvement. The best design still depends on context.

A unit-of-work surface for querying and saving entities.

DbContext and DbSet

1DbSet query

2DbContext tracks changes

3SaveChanges → database

What to notice

The application creates a new context for every small operation, losing a coherent unit of work.

C# / HTTP / SQL sample

A design to question

var user = new User { Name = "Mina" };
using var db = new AppDbContext();
db.Users.Add(user);
db.SaveChanges();

// Each method creates another context.

Right or wrong: is this version a good fit?

Quick knowledge check

Put your interview hat on

1 / 4

Which EF Core object typically represents a unit of work and change tracker?

Based on our SQL & EF interview guide. Examples are simplified for learning; adapt patterns to the requirements of your application.