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Explain Entity Framework Core and its advantages. سهل
Entity Framework Core (EF Core) is Microsoft’s modern Object-Relational Mapper (ORM) for .NET. It lets you work with databases using C# classes instead of SQL directly.
Advantages:
- Cross-platform (works with .NET Core)
- Supports LINQ queries
- Change tracking and relationship management
- Migrations for schema evolution
- Works with many databases (SQL Server, PostgreSQL, MySQL, SQLite)
What are Migrations in EF Core? سهل
A way to evolve the database schema as your models change. They keep C# models and DB schema in sync.
Example commands:
Add-Migration InitialCreateUpdate-Database
What is different between Code First and Db First? سهل
| Approach | Code First | Database First |
|---|---|---|
| Start point | Define C# classes (models) | Start from existing database schema |
| Schema creation | EF creates/updates DB schema via migrations | EF generates models from DB |
| Best for | Greenfield projects (new DB) | Legacy/existing databases |
What is Database Seeding? سهل
Seeding = pre-populating the database with initial/static data. Done in OnModelCreating using .HasData().
Example:
modelBuilder.Entity<Role>().HasData(new Role { Id = 1, Name = "Admin" });
What is the difference between SaveChanges() and SaveChangesAsync()? سهل
- SaveChanges(): Synchronous, blocks the thread until DB operation finishes.
- SaveChangesAsync(): Asynchronous, does not block, returns a Task. Use SaveChangesAsync() in web apps for better scalability.