使用实体框架插入/保存具有嵌套子实体的实体

// 定义实体类和子实体类
public class Order
{
    public int OrderId { get; set; }
    public string OrderNumber { get; set; }
    public List<OrderItem> OrderItems { get; set; }
}

public class OrderItem
{
    public int OrderItemId { get; set; }
    public string ProductName { get; set; }
    public decimal Price { get; set; }
}

// 创建数据库上下文
public class MyDbContext : DbContext
{
    public DbSet<Order> Orders { get; set; }
    public DbSet<OrderItem> OrderItems { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("连接字符串");
    }
}

// 创建实体对象并插入/保存
public void InsertOrderWithNestedEntities()
{
    using (var context = new MyDbContext())
    {
        var order = new Order
        {
            OrderNumber = "ORD001",
            OrderItems = new List<OrderItem>
            {
                new OrderItem { ProductName = "Product 1", Price = 10.99m },
                new OrderItem { ProductName = "Product 2", Price = 20.99m }
            }
        };

        context.Orders.Add(order);
        context.SaveChanges();
    }
}