LINQ ื ืื ืกื ื-.NET ืืฉืคืช ืื ืืคืืืฆืื ืืืฉื ืืืืงื. LINQ ื-SQL ืืืืง ืืื ื ืืืคืฉืจ ืื ืืชืงืฉืจ ืืฆืืจื ื ืืื ืืืื ืขื DBMS ืืืืฆืขืืช, ืืืฉื, Entity Framework. ืขื ืืืช, ืืฉืชืืฉืื ืื ืืขืชืื ืงืจืืืืช ืืืื, ืืคืชืืื ืฉืืืืื ืืืืืง ืืืื ืกืื ืฉื ืฉืืืืชืช SQL ืืคืืง ืืกืคืง ืื ืืชื ืืฉืืืืชื, ืืืงืจื ืฉืื Entity Framework.
ืืืื ื ืกืชืื ืขื ืฉืชื ื ืงืืืืช ืขืืงืจืืืช ืืืืฆืขืืช ืืืืื.
ืืฉื ืื, ืฆืืจ ืืกื ื ืชืื ืื Test ื-SQL Server, ืืฆืืจ ืื ืฉืชื ืืืืืืช ืืืืฆืขืืช ืืฉืืืืชื ืืืื:
ืืฆืืจืช ืืืืืืช
USE [TEST]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Ref](
[ID] [int] NOT NULL,
[ID2] [int] NOT NULL,
[Name] [nvarchar](255) NOT NULL,
[InsertUTCDate] [datetime] NOT NULL,
CONSTRAINT [PK_Ref] PRIMARY KEY CLUSTERED
(
[ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[Ref] ADD CONSTRAINT [DF_Ref_InsertUTCDate] DEFAULT (getutcdate()) FOR [InsertUTCDate]
GO
USE [TEST]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Customer](
[ID] [int] NOT NULL,
[Name] [nvarchar](255) NOT NULL,
[Ref_ID] [int] NOT NULL,
[InsertUTCDate] [datetime] NOT NULL,
[Ref_ID2] [int] NOT NULL,
CONSTRAINT [PK_Customer] PRIMARY KEY CLUSTERED
(
[ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[Customer] ADD CONSTRAINT [DF_Customer_Ref_ID] DEFAULT ((0)) FOR [Ref_ID]
GO
ALTER TABLE [dbo].[Customer] ADD CONSTRAINT [DF_Customer_InsertUTCDate] DEFAULT (getutcdate()) FOR [InsertUTCDate]
GO
ืืขืช ื ืืืืก ืืช ืืืืช Ref ืขื ืืื ืืคืขืืช ืืกืงืจืืคื ืืื:
ืืืืื ืืืืช ื-Ref
USE [TEST]
GO
DECLARE @ind INT=1;
WHILE(@ind<1200000)
BEGIN
INSERT INTO [dbo].[Ref]
([ID]
,[ID2]
,[Name])
SELECT
@ind
,@ind
,CAST(@ind AS NVARCHAR(255));
SET @ind=@ind+1;
END
GO
ืืื ื ืืื ืืืืคื ืืืื ืืช ืืืืช ืืืงืืืืช ืืืืฆืขืืช ืืกืงืจืืคื ืืื:
ืืืืืก ืืืืช ืืืงืืืืช
USE [TEST]
GO
DECLARE @ind INT=1;
DECLARE @ind_ref INT=1;
WHILE(@ind<=12000000)
BEGIN
IF(@ind%3=0) SET @ind_ref=1;
ELSE IF (@ind%5=0) SET @ind_ref=2;
ELSE IF (@ind%7=0) SET @ind_ref=3;
ELSE IF (@ind%11=0) SET @ind_ref=4;
ELSE IF (@ind%13=0) SET @ind_ref=5;
ELSE IF (@ind%17=0) SET @ind_ref=6;
ELSE IF (@ind%19=0) SET @ind_ref=7;
ELSE IF (@ind%23=0) SET @ind_ref=8;
ELSE IF (@ind%29=0) SET @ind_ref=9;
ELSE IF (@ind%31=0) SET @ind_ref=10;
ELSE IF (@ind%37=0) SET @ind_ref=11;
ELSE SET @ind_ref=@ind%1190000;
INSERT INTO [dbo].[Customer]
([ID]
,[Name]
,[Ref_ID]
,[Ref_ID2])
SELECT
@ind,
CAST(@ind AS NVARCHAR(255)),
@ind_ref,
@ind_ref;
SET @ind=@ind+1;
END
GO
ืืคืืื, ืงืืืื ื ืฉืชื ืืืืืืช, ืืืช ืืื ืืืืื ืืืชืจ ืืืืืืื ืฉืืจืืช ื ืชืื ืื, ืืืฉื ืืื ืืขืืช ืืืชืจ ื-1 ืืืืืื ืฉืืจืืช ื ืชืื ืื.
ืืขืช ื-Visual Studio ืืชื ืฆืจืื ืืืฆืืจ ืคืจืืืงื ืืืืงื ืฉื Visual C# Console App (.NET Framework):
ืืืืจ ืืื, ืขืืื ืืืืกืืฃ ืกืคืจืื ืืื ืฉืืกืืจืช ืืืฉืืช ืชืืฆืืจ ืืื ืืจืืงืฆืื ืขื ืืกื ืื ืชืื ืื.
ืืื ืืืืกืืฃ ืืืชื, ืืืฅ ืืืืฆื ืืื ืืช ืขื ืืคืจืืืงื ืืืืจ ื ืืืื ืืืืืืช NuGet ืืชืคืจืื ืืืงืฉืจ:
ืืืืจ ืืื, ืืืืื ื ืืืื ืืืืืืืช ืฉื NuGet ืฉืืืคืืข, ืืื ืืช ืืืืื "Entity Framework" ืืืืื ืืืืคืืฉ ืืืืจ ืืืืืืช Entity Framework ืืืชืงื ืืืชื:
ืืืืจ ืืื, ืืงืืืฅ App.config, ืืืืจ ืกืืืจืช ืืืืื ื configSections, ืขืืื ืืืืกืืฃ ืืช ืืืืืง ืืื:
<connectionStrings>
<add name="DBConnection" connectionString="data source=ะะะฏ_ะญะะะะะะะฏะ ะ_MSSQL;Initial Catalog=TEST;Integrated Security=True;" providerName="System.Data.SqlClient" />
</connectionStrings>
ื-connectionString ืืชื ืฆืจืื ืืืืื ืืช ืืืจืืืช ืืืืืืจ.
ืขืืฉืื ืืืื ื ืืฆืืจ 3 ืืืฉืงืื ืืงืืฆืื ื ืคืจืืื:
- ืืืืขืช ืืืฉืง IBaseEntityID
namespace TestLINQ { public interface IBaseEntityID { int ID { get; set; } } }
- ืืืืขืช ืืืฉืง IBaseEntityName
namespace TestLINQ { public interface IBaseEntityName { string Name { get; set; } } }
- ืืืฉืื ืืืฉืง IBaseNameInsertUTCDate
namespace TestLINQ { public interface IBaseNameInsertUTCDate { DateTime InsertUTCDate { get; set; } } }
ืืืงืืืฅ ื ืคืจื ื ืืฆืืจ ืืืืงื ืืกืืกืืช BaseEntity ืขืืืจ ืฉืชื ืืืฉืืืืช ืฉืื ื, ืฉืชืืืื ืฉืืืช ื ืคืืฆืื:
ืืืฉืื ืืืืงืช ืืืกืืก BaseEntity
namespace TestLINQ
{
public class BaseEntity : IBaseEntityID, IBaseEntityName, IBaseNameInsertUTCDate
{
public int ID { get; set; }
public string Name { get; set; }
public DateTime InsertUTCDate { get; set; }
}
}
ืืืืจ ืืื, ื ืืฆืืจ ืืช ืฉืชื ืืืฉืืืืช ืฉืื ื ืืงืืฆืื ื ืคืจืืื:
- ืืืฉืื ืืืืงื Ref
using System.ComponentModel.DataAnnotations.Schema; namespace TestLINQ { [Table("Ref")] public class Ref : BaseEntity { public int ID2 { get; set; } } }
- ืืืฉืื ืืืืงืช ืืืงืื
using System.ComponentModel.DataAnnotations.Schema; namespace TestLINQ { [Table("Customer")] public class Customer: BaseEntity { public int Ref_ID { get; set; } public int Ref_ID2 { get; set; } } }
ืขืืฉืื ืืืื ื ืืฆืืจ ืืงืฉืจ UserContext ืืงืืืฅ ื ืคืจื:
ืืืฉืื ืืืืงืช UserContex
using System.Data.Entity;
namespace TestLINQ
{
public class UserContext : DbContext
{
public UserContext()
: base("DbConnection")
{
Database.SetInitializer<UserContext>(null);
}
public DbSet<Customer> Customer { get; set; }
public DbSet<Ref> Ref { get; set; }
}
}
ืงืืืื ื ืคืชืจืื ืืืื ืืืืฆืืข ืืืื ื ืืืคืืืืืืฆืื ืขื LINQ ื-SQL ืืจื EF ืขืืืจ MS SQL Server:
ืืขืช ืืื ืืช ืืงืื ืืื ืืงืืืฅ Program.cs:
ืงืืืฅ Program.cs
using System;
using System.Collections.Generic;
using System.Linq;
namespace TestLINQ
{
class Program
{
static void Main(string[] args)
{
using (UserContext db = new UserContext())
{
var dblog = new List<string>();
db.Database.Log = dblog.Add;
var query = from e1 in db.Customer
from e2 in db.Ref
where (e1.Ref_ID == e2.ID)
&& (e1.Ref_ID2 == e2.ID2)
select new { Data1 = e1.Name, Data2 = e2.Name };
var result = query.Take(1000).ToList();
Console.WriteLine(dblog[1]);
Console.ReadKey();
}
}
}
}
ืืืืจ ืืื, ืืืื ื ืฉืืง ืืช ืืคืจืืืงื ืฉืื ื.
ืืกืืื ืืขืืืื ืืืฆืื ืืืกืืฃ ืืืืจืื ืืืืื:
ืฉืืืืชืช SQL ืฉื ืืฆืจื
SELECT TOP (1000)
[Extent1].[Ref_ID] AS [Ref_ID],
[Extent1].[Name] AS [Name],
[Extent2].[Name] AS [Name1]
FROM [dbo].[Customer] AS [Extent1]
INNER JOIN [dbo].[Ref] AS [Extent2] ON ([Extent1].[Ref_ID] = [Extent2].[ID]) AND ([Extent1].[Ref_ID2] = [Extent2].[ID2])
ืืืืืจ, ืืืืคื ืืืื, ืฉืืืืชืช LINQ ืืฆืจื ืฉืืืืชืช SQL ื-DBMS ืฉื MS SQL Server ืืฆืืจื ืืืื ืืืื.
ืืขืช ื ืฉื ื ืืช ืชื ืื ื-AND ื-OR ืืฉืืืืชืช LINQ:
ืฉืืืืชืช LINQ
var query = from e1 in db.Customer
from e2 in db.Ref
where (e1.Ref_ID == e2.ID)
|| (e1.Ref_ID2 == e2.ID2)
select new { Data1 = e1.Name, Data2 = e2.Name };
ืืืืื ื ืฉืืง ืืช ืืืคืืืงืฆืื ืฉืื ื ืฉืื.
ืืืืฆืืข ืืงืจืืก ืขื ืฉืืืื ืขืงื ืืื ืืืฆืืข ืืคืงืืื ืืขืืื ืขื 30 ืฉื ืืืช:
ืื ืืชื ืืกืชืื ืขื ืืฉืืืืชื ืฉื ืืฆืจื ืขื ืืื LINQ:
, ืื ืืชื ืืืื ืืืืื ืฉืืืืืจื ืืชืจืืฉืช ืืืืฆืขืืช ืืืืคืื ืืงืจืืืืื ืืช ืฉื ืฉืชื ืงืืืฆืืช (ืืืืืืช):
ืฉืืืืชืช SQL ืฉื ืืฆืจื
SELECT TOP (1000)
[Extent1].[Ref_ID] AS [Ref_ID],
[Extent1].[Name] AS [Name],
[Extent2].[Name] AS [Name1]
FROM [dbo].[Customer] AS [Extent1]
CROSS JOIN [dbo].[Ref] AS [Extent2]
WHERE [Extent1].[Ref_ID] = [Extent2].[ID] OR [Extent1].[Ref_ID2] = [Extent2].[ID2]
ืืื ื ืฉืืชื ืืช ืฉืืืืชืช LINQ ืืืืคื ืืื:
ืฉืืืืชืช LINQ ืืืคืืืืืืช
var query = (from e1 in db.Customer
join e2 in db.Ref
on e1.Ref_ID equals e2.ID
select new { Data1 = e1.Name, Data2 = e2.Name }).Union(
from e1 in db.Customer
join e2 in db.Ref
on e1.Ref_ID2 equals e2.ID2
select new { Data1 = e1.Name, Data2 = e2.Name });
ืื ื ืงืื ืืช ืฉืืืืชืช ื-SQL ืืืื:
ืฉืืืืชืช SQL
SELECT
[Limit1].[C1] AS [C1],
[Limit1].[C2] AS [C2],
[Limit1].[C3] AS [C3]
FROM ( SELECT DISTINCT TOP (1000)
[UnionAll1].[C1] AS [C1],
[UnionAll1].[Name] AS [C2],
[UnionAll1].[Name1] AS [C3]
FROM (SELECT
1 AS [C1],
[Extent1].[Name] AS [Name],
[Extent2].[Name] AS [Name1]
FROM [dbo].[Customer] AS [Extent1]
INNER JOIN [dbo].[Ref] AS [Extent2] ON [Extent1].[Ref_ID] = [Extent2].[ID]
UNION ALL
SELECT
1 AS [C1],
[Extent3].[Name] AS [Name],
[Extent4].[Name] AS [Name1]
FROM [dbo].[Customer] AS [Extent3]
INNER JOIN [dbo].[Ref] AS [Extent4] ON [Extent3].[Ref_ID2] = [Extent4].[ID2]) AS [UnionAll1]
) AS [Limit1]
ืืืจืื ืืฆืขืจ, ืืฉืืืืชืืช LINQ ืืืื ืืืืืช ืจืง ืชื ืื ืืฆืืจืคืืช ืืื, ืื ืืื ืืคืฉืจ ืืขืฉืืช ืฉืืืืชื ืฉืืืช ืขืจื ืืืืฆืขืืช ืฉืชื ืฉืืืืชืืช ืืื ืชื ืื ืืืืืจ ืืื ืืฉืื ืืืชื ืืจื Union ืืื ืืืกืืจ ืืคืืืืืืช ืืื ืืฉืืจืืช.
ืื, ืืฉืืืืชืืช ืืืจื ืืื ืื ืืืื ืฉืืืช ืขืจื, ืชืื ืืชืืฉืืืช ืืื ืฉืืืชืื ืฉืืืืืจื ืฉืืจืืช ืืคืืืืช ืฉืืืืช. ืขื ืืืช, ืืืืื ืืืืืชืืื, ืืื ืฆืืจื ืืฉืืจืืช ืืคืืืืช ืฉืืืืช ืืื ืฉืื ืื ืกืื ืืืืคืืจ ืืื.
ืืขืช ื ืฉืืื ืืช ืชืืื ืืืช ืืืืฆืืข ืฉื ืฉืชื ืืฉืืืืชืืช ืืืื:
- ืขืืืจ CROSS JOIN ืืื ืืืืฆืืข ืืืืืฆืข ืืื 195 ืฉื ืืืช:
- ืขืืืจ INNER JOIN-UNION ืืื ืืืืฆืืข ืืืืืฆืข ืืื ืคืืืช ื-24 ืฉื ืืืช:
ืืคื ืฉื ืืชื ืืจืืืช ืืืชืืฆืืืช, ืขืืืจ ืฉืชื ืืืืืืช ืขื ืืืืืื ื ืจืฉืืืืช, ืฉืืืืชืช LINQ ืืืืืืืช ืืื ืืืืจื ืคื ืืื ืืืฉืืืืชื ืืื ืืืคืืืืืืช.
ืขืืืจ ืืืคืฉืจืืช ืขื AND ืืชื ืืื, ืฉืืืืชืช LINQ ืืืืคืก:
ืฉืืืืชืช LINQ
var query = from e1 in db.Customer
from e2 in db.Ref
where (e1.Ref_ID == e2.ID)
&& (e1.Ref_ID2 == e2.ID2)
select new { Data1 = e1.Name, Data2 = e2.Name };
ืืืขื ืชืืื ืชืืืืฆืจ ืฉืืืืชืช SQL ืื ืืื ื, ืฉืชืคืขื ืืืืืฆืข ืชืื ืฉื ืืื ืืืช ืืขืจื:
ืื ืขืืืจ ืื ืืคืืืฆืืืช LINQ to Objects ืืืงืื ืฉืืืืชื ืืื:
ืฉืืืืชืช LINQ (ืืคืฉืจืืช ืจืืฉืื ื)
var query = from e1 in seq1
from e2 in seq2
where (e1.Key1==e2.Key1)
&& (e1.Key2==e2.Key2)
select new { Data1 = e1.Data, Data2 = e2.Data };
ืืชื ืืืื ืืืฉืชืืฉ ืืฉืืืืชื ืืื:
ืฉืืืืชืช LINQ (ืืคืฉืจืืช ืจืืฉืื ื)
var query = from e1 in seq1
join e2 in seq2
on new { e1.Key1, e1.Key2 } equals new { e2.Key1, e2.Key2 }
select new { Data1 = e1.Data, Data2 = e2.Data };
ืฉื:
ืืืืจืช ืฉื ื ืืขืจืืื
Para[] seq1 = new[] { new Para { Key1 = 1, Key2 = 2, Data = "777" }, new Para { Key1 = 2, Key2 = 3, Data = "888" }, new Para { Key1 = 3, Key2 = 4, Data = "999" } };
Para[] seq2 = new[] { new Para { Key1 = 1, Key2 = 2, Data = "777" }, new Para { Key1 = 2, Key2 = 3, Data = "888" }, new Para { Key1 = 3, Key2 = 5, Data = "999" } };
, ืืกืื Para ืืืืืจ ืืืืงืื:
ืืืืจืช ืกืื ืคืืจื
class Para
{
public int Key1, Key2;
public string Data;
}
ืืคืืื, ืืื ื ืืื ืืืืืื ืืืืคืืืืืืฆืื ืฉื ืฉืืืืชืืช LINQ ื-MS SQL Server.
ืืืจืื ืืฆืขืจ, ืืคืืื ืืคืชืื .NET ืื ืืกืื ืืืืืืืื ืฉืืืืื ืฉืื ืฆืจืืืื ืืืืื ืื ืขืืฉืืช ืืืืจืืืช ืฉืื ืืฉืชืืฉืื ืืืืืจื ืืงืืขืื. ืืืจืช, ืื ืืืคืืื ืืงืื ืคืืืืจืืืจืื ืืืืืืื ืืืืืื ืคืฆืฆืช ืืื ืืขืชืื ืื ืืขืช โโืงื ื ืืืืื ืฉื ืคืชืจืื ืืชืืื ื ืืื ืขื ืฉืื ืืืื ืงืืื ืืชื ืื ืืกืืืื ืืืืฆืื ืืื.
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