review-bench/andresharpe_dotbot/create-migration

public class User
{
    public int Id { get; set; }
    public string Email { get; set; } // New property
    public DateTime CreatedAt { get; set; }
}

public class AppDbContext : DbContext
{
    public DbSet<User> Users { get; set; }
    
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>(entity =>
        {
            entity.HasKey(e => e.Id);
            entity.Property(e => e.Email).IsRequired().HasMaxLength(255);
            entity.HasIndex(e => e.Email).IsUnique();
        });
    }
}

dotnet ef migrations add AddEmailToUser

dotnet ef database update

migrationBuilder.AddColumn<string>(
    name: "Email",
    table: "Users",
    type: "nvarchar(255)",
    maxLength: 255,
    nullable: false,
    defaultValue: "");

migrationBuilder.AlterColumn<string>(
    name: "Name",
    table: "Users",
    type: "nvarchar(100)",
    maxLength: 100,
    nullable: false,
    oldClrType: typeof(string),
    oldType: "nvarchar(50)",
    oldMaxLength: 50);

migrationBuilder.CreateIndex(
    name: "IX_Users_Email",
    table: "Users",
    column: "Email",
    unique: true);

migrationBuilder.AddForeignKey(
    name: "FK_Orders_Users_UserId",
    table: "Orders",
    column: "UserId",
    principalTable: "Users",
    principalColumn: "Id",
    onDelete: ReferentialAction.Cascade);

protected override void Up(MigrationBuilder migrationBuilder)
{
    // 1. Schema change
    migrationBuilder.AddColumn<string>(
        name: "FullName",
        table: "Users",
        nullable: true);
    
    // 2. Data migration
    migrationBuilder.Sql(@"
        UPDATE Users 
        SET FullName = FirstName + ' ' + LastName
        WHERE FirstName IS NOT NULL AND LastName IS NOT NULL
    ");
    
    // 3. Make column required after data is populated
    migrationBuilder.AlterColumn<string>(
        name: "FullName",
        table: "Users",
        nullable: false);
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Role>().HasData(
        new Role { Id = 1, Name = "Admin" },
        new Role { Id = 2, Name = "User" }
    );
}

protected override void Down(MigrationBuilder migrationBuilder)
{
    // Reverse the changes made in Up()
    migrationBuilder.DropColumn(
        name: "Email",
        table: "Users");
}

migrationBuilder.RenameColumn(
    name: "OldName",
    table: "Users",
    newName: "NewName");

migrationBuilder.DropTable(
    name: "ObsoleteTable");

modelBuilder.Entity<UserRole>()
    .HasKey(ur => new { ur.UserId, ur.RoleId });