EF基礎篇-Code First

Code First 通過代碼反向生成資料庫，無需關心資料庫方面

1 建立一個控制台項目

2 打開NuGet程式包管理，添加EntityFramework

添加完成後檢視是否有如下兩個引用

3 代碼編寫及配置

建立Goods類

class Goods
	{
		[Key]
		public int GID { get; set; }
		public string GName { get; set; }
		public int GPrice { get; set; }
		public int Shelf_SID { get; set; }
	}           

建立Shelves類

class Shelves
	{
		[Key]
		public int SID { get; set; }
		public string SPosition { get; set; }
		public string SName { get; set; }
	}           

建立上下文SaleContext

class SaleContext:DbContext
	{
		public SaleContext():base("name=SaleMarket")
		{
		}
		
		public virtual DbSet<Goods> Goods { get; set; }
		
		public virtual DbSet<Shelves> Shelf { get; set; }
	}           

App.config中添加資料庫連接配接

<connectionStrings>
	<add name="SaleMarket" connectionString="data source=IP;initial Catalog=SaleMarket;user id=sa;password=*****;" providerName="System.Data.SqlClient"/>
</connectionStrings>           

4 資料庫建立及執行個體操作

using(var smContext=new SaleContext())
	{
		if (smContext.Database.CreateIfNotExists())
		{
			Console.WriteLine("建立成功");
		}
		else
		{
			Console.WriteLine("資料庫已存在");
		}
		//CRUD
		List<Shelves> s1 = new List<Shelves>
		{
			new Shelves
			{
				SID=1,
				SName="糖果區",
				SPosition="1L-09N",
			},
			new Shelves
			{
				SID=2,
				SName="瓜子區",
				SPosition="1L-08N",
			}
		};
		List<Goods> g1 = new List<Goods>
		{
			new Goods
			{
				GID=1,
				GName="大白兔",
				GPrice=16
				Shelf_SID=1
			},
			new Goods
			{
				GID=2,
				GName="巧克力",
				GPrice=32,
				Shelf_SID=1
			},
			new Goods
			{
				GID=3，
				GName="焦糖味"，
				GPrice=15,
				Shelf_SID=2
			},
			new Goods
			{
				GID=4,
				GName="原味",
				GPrice=12,
				Shelf_SID=2
			},
			new Goods
			{
				GID=5,
				GName="五香味",
				GPrice=10，
				Shelf_SID=2
			},
		};
		smContext.Shelf.AddRange(s1);
		smContext.Goods.AddRange(g1);
		smContex.SaveChanges();
		var p = smContext.Goods.Join(smContext.Shelf,g=>g.Shelf_SID,s=>s.SID,(g,s)=>new { g.GName,g.GPrice,s.SName,s.SPosition }).WHere(gs=>gs.GPrice>16);
		foreach (var item in p)
		{
			Console.WriteLine($"{item.GName}在{item.SPosition}的{item.SName},價格是{item.GPrice}");
		
		}
	}
	Console.ReadKey();           

打開資料庫檢視，資料庫已建立

結果顯示