c# .net entity framework prefill database code example

Example 1: seeding in ef6

public class SchoolContext: DbContext 
{
    public SchoolContext(): base("SchoolDB") 
    {
        Database.SetInitializer(new SchoolDBInitializer());
    }
    
    public DbSet<Student> Students { get; set; }
    public DbSet<Standard> Standards { get; set; }
}


public class SchoolDBInitializer : DropCreateDatabaseAlways<SchoolDBContext>
{
    protected override void Seed(SchoolDBContext context)
    {
        IList<Standard> defaultStandards = new List<Standard>();

        defaultStandards.Add(new Standard() { StandardName = "Standard 1", Description = "First Standard" });
        defaultStandards.Add(new Standard() { StandardName = "Standard 2", Description = "Second Standard" });
        defaultStandards.Add(new Standard() { StandardName = "Standard 3", Description = "Third Standard" });

        context.Standards.AddRange(defaultStandards);

        base.Seed(context);
    }
}

Example 2: database hasData method C#

// it goes into class ApplicationDbContext : DbContext
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Author>().HasData(
        new Author
        {
            AuthorId = 1,
            FirstName = "William",
            LastName = "Shakespeare"
        }
    );
    modelBuilder.Entity<Book>().HasData(
        new Book { BookId = 1, AuthorId = 1, Title = "Hamlet" },
        new Book { BookId = 2, AuthorId = 1, Title = "King Lear" },
        new Book { BookId = 3, AuthorId = 1, Title = "Othello" }
    );

   /*further relational instructions may come here, like:
        modelBuilder.Entity<Author>()
        .HasMany<Book>(a => a.Books)
        .WithOne(b => b.Author)
        .HasForeignKey(b => b.AuthorId);
}