簡單 Coding

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讓我們從熟悉的 Visual Studio 2015 開始吧！

1. 建立新的 Console 專案

2. 打開 Package Manager Console

3. 安裝 Microsoft.EntityFrameworkCore.SqlServer 套件( 能連接 SqlServer 的 EF Core 核心套件 )

Install-Package Microsoft.EntityFrameworkCore.SqlServer

 4. 安裝 Microsoft.EntityFrameworkCore.Tools ( 像是 migration 指令會用到 )

Install-Package Microsoft.EntityFrameworkCore.Tools –Pre

5. 建立一個 Models.cs 類別，裡面放 EF 要建立資料庫相關代碼，

using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EFCoreNET462
{
	public class Ex1Context : DbContext
	{
		public DbSet<Order> Orders { get; set; }
		public DbSet<OrderDetail> OrderDetails { get; set; }

		protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
		{
			optionsBuilder.UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=EFCoreExample1DB;Trusted_Connection=True;");
		}
	}

	public class Order
	{
		public int OrderId { get; set; }
		public DateTime CreateDate { get; set; }
		public List<OrderDetail> Details { get; set; }
	}

	public class OrderDetail
	{
		public int OrderDetailId { get; set; }
		public string ProductNo { get; set; }

		public int OrderId { get; set; }
		public Order Order { get; set; }
	}
}

6. 在 Package Manager Console 輸入 

Add-Migration MyFirstMigration

這個會建立 Migrations 資料夾，裡面包含 ModelSnapshot.cs 結尾的檔案與 時間戳_MyFirstMigration.cs，

主要是這個指令會偵測程式碼中的 Ex1Context  相關代碼，去產生這些與資料庫結構有關的代碼

7. 接著一樣在 Package Manager Console 輸入

Update-Database

這個動作就會依照 Migrations 的設定，建立資料庫與 Tables

8. 在 Program.cs 加入以下代碼

using System;
using System.Linq;

namespace EFCoreNET462
{
	class Program
	{
		static void Main(string[] args)
		{
			using (var db = new Ex1Context())
			{
				if (! db.Orders.Any())
				{
					db.Orders.Add(new Order
					{
						 CreateDate = DateTime.Now
					});

					db.SaveChanges();
				}

				var list = db.Orders.ToList();
				foreach (var item in list)
				{
					Console.WriteLine($"{item.OrderId}: {item.CreateDate}");
				}
				Console.Read();
			}
		}
	}
	
}

 執行後應該會看到 

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接著換 dotnet，其中若想寫程式的部分，可以用 Visual Studio Code，

1. 用命令提示字元建立先建立要放專案檔案的資料夾，並切換資料夾

mkdir EFCoreNETCore10
cd EFCoreNETCore10

2. 然後建立專案，然後第一次記得都要還原套件

dotnet new
dotnet restore

 3. 在用 Visual Studio Code 的指令來開啟(或用記事本編輯也可)

code .

4. project.json 加入 Microsoft.EntityFrameworkCore.SqlServer、Microsoft.EntityFrameworkCore.Design、Microsoft.EntityFrameworkCore.Tools

{
  "version": "1.0.0-*",
  "buildOptions": {
    "debugType": "portable",
    "emitEntryPoint": true
  },
  "dependencies": {
    "Microsoft.EntityFrameworkCore.SqlServer":"1.0.1",
    "Microsoft.EntityFrameworkCore.Design": {
      "version": "1.0.0-preview2-final",
      "type": "build" 
    }
  },
  "frameworks": {
    "netcoreapp1.0": {
      "dependencies": {
        "Microsoft.NETCore.App": {
          "type": "platform",
          "version": "1.0.0"
        }
      },
      "imports": "dnxcore50"
    }
  },
  "tools": {
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final" 
  } 
}

5. 建立 models.cs 加入以下代碼

using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;

namespace EFCoreNETCore10
{
    public class Ex1Context : DbContext
    {
        public DbSet<Order> Orders { get; set; }
        public DbSet<OrderDetail> OrderDetails { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=EFCoreExample2DB;Trusted_Connection=True;");
        }
    }

    public class Order
    {
        public int OrderId { get; set; }
        public DateTime CreateDate { get; set; }
        public List<OrderDetail> Details { get; set; }
    }

    public class OrderDetail
    {
        public int OrderDetailId { get; set; }
        public string ProductNo { get; set; }

        public int OrderId { get; set; }
        public Order Order { get; set; }
    }
}

6. 用命令提示字元建立 migrations

dotnet ef migrations add MyFirstMigration

7. 在將資料庫建立起來

dotnet ef database update

8. Program.cs 加入測試代碼

using System;
using System.Linq;

namespace EFCoreNETCore10
{
    class Program
    {
        static void Main(string[] args)
        {
            using (var db = new Ex1Context())
            {
                if (!db.Orders.Any())
                {
                    db.Orders.Add(new Order
                    {
                        CreateDate = DateTime.Now
                    });

                    db.SaveChanges();
                }

                var list = db.Orders.ToList();
                foreach (var item in list)
                {
                    Console.WriteLine($"{item.OrderId}: {item.CreateDate}");
                }
                Console.Read();
            }
        }
    }

}

9. 執行看看

dotnet run

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參考文章

Console Application to New Database

讓我們 Core 在一起：ASP.NET Core & .NET Core