EFで短いクエリを作成するには？

Question

このコードブロックは、データベースからジョブ注文情報を収集し、複数のテーブルを結合し、オブジェクトを返します。まあ、すべてが魅力として動作しますが、遅すぎますか？

これはジョブを実行するコードです。

public IQueryable<object> JsonGetJobOrdersBy(int status, int companyID) 
{ 

    IQueryable<object> result = this.db.JobOrder.Where(j => j.Status == status && j.RelatedCompanyID == companyID) 
     .Select(x => new 
     { 
      JobOrderID = x.JobOrderID, 
      CustomerName = x.Customers.Name, 
      CustomerSurName = x.Customers.Surname, 
      SerialNo = x.SerialNo, 
      DeviceName = x.DeviceModel.DeviceName, 
      BrandName = x.DeviceModel.DeviceBrand.BrandName, 
      State = x.State, 
      ServiceType = x.ServiceType, 
      InsertDate = x.InsertDate, 
      StaffFirstName = x.AttendedStaff.FirstOrDefault().SystemUsers.StaffFirstName, 
      StaffSurName = x.AttendedStaff.FirstOrDefault().SystemUsers.StaffSurName, 
      Importance = x.Importance 
     }).OrderByDescending(x => x.JobOrderID); 

    return result; 
} 

そして、このブロックは、その長いクエリがOKであるかどうまあ、私が言うことができなかったちょっと長いSQL

SELECT 
[Project6].[JobOrderID] AS [JobOrderID], 
[Project6].[Name] AS [Name], 
[Project6].[Surname] AS [Surname], 
[Project6].[SerialNo] AS [SerialNo], 
[Project6].[DeviceName] AS [DeviceName], 
[Project6].[BrandName] AS [BrandName], 
[Project6].[State] AS [State], 
[Project6].[ServiceType] AS [ServiceType], 
[Project6].[InsertDate] AS [InsertDate], 
[Project6].[StaffFirstName] AS [StaffFirstName], 
[Project6].[StaffSurName] AS [StaffSurName], 
[Project6].[Importance] AS [Importance] 
FROM (SELECT 
    [Project5].[JobOrderID] AS [JobOrderID], 
    [Project5].[SerialNo] AS [SerialNo], 
    [Project5].[Importance] AS [Importance], 
    [Project5].[ServiceType] AS [ServiceType], 
    [Project5].[State] AS [State], 
    [Project5].[InsertDate] AS [InsertDate], 
    [Project5].[Name] AS [Name], 
    [Project5].[Surname] AS [Surname], 
    [Project5].[DeviceName] AS [DeviceName], 
    [Project5].[BrandName] AS [BrandName], 
    [Project5].[StaffFirstName] AS [StaffFirstName], 
    [Extent8].[StaffSurName] AS [StaffSurName] 
    FROM (SELECT 
     [Project3].[JobOrderID] AS [JobOrderID], 
     [Project3].[SerialNo] AS [SerialNo], 
     [Project3].[Importance] AS [Importance], 
     [Project3].[ServiceType] AS [ServiceType], 
     [Project3].[State] AS [State], 
     [Project3].[InsertDate] AS [InsertDate], 
     [Project3].[Name] AS [Name], 
     [Project3].[Surname] AS [Surname], 
     [Project3].[DeviceName] AS [DeviceName], 
     [Project3].[BrandName] AS [BrandName], 
     [Project3].[StaffFirstName] AS [StaffFirstName], 
     (SELECT TOP (1) 
      [Extent7].[StaffID] AS [StaffID] 
      FROM [dbo].[AttendedStaff] AS [Extent7] 
      WHERE [Project3].[JobOrderID] = [Extent7].[JobOrderID]) AS [C1] 
     FROM (SELECT 
      [Project2].[JobOrderID] AS [JobOrderID], 
      [Project2].[SerialNo] AS [SerialNo], 
      [Project2].[Importance] AS [Importance], 
      [Project2].[ServiceType] AS [ServiceType], 
      [Project2].[State] AS [State], 
      [Project2].[InsertDate] AS [InsertDate], 
      [Project2].[Name] AS [Name], 
      [Project2].[Surname] AS [Surname], 
      [Project2].[DeviceName] AS [DeviceName], 
      [Project2].[BrandName] AS [BrandName], 
      [Extent6].[StaffFirstName] AS [StaffFirstName] 
      FROM (SELECT 
       [Extent1].[JobOrderID] AS [JobOrderID], 
       [Extent1].[SerialNo] AS [SerialNo], 
       [Extent1].[Importance] AS [Importance], 
       [Extent1].[ServiceType] AS [ServiceType], 
       [Extent1].[State] AS [State], 
       [Extent1].[InsertDate] AS [InsertDate], 
       [Extent2].[Name] AS [Name], 
       [Extent2].[Surname] AS [Surname], 
       [Extent3].[DeviceName] AS [DeviceName], 
       [Extent4].[BrandName] AS [BrandName], 
       (SELECT TOP (1) 
        [Extent5].[StaffID] AS [StaffID] 
        FROM [dbo].[AttendedStaff] AS [Extent5] 
        WHERE [Extent1].[JobOrderID] = [Extent5].[JobOrderID]) AS [C1] 
       FROM [dbo].[JobOrder] AS [Extent1] 
       INNER JOIN [dbo].[Customers] AS [Extent2] ON [Extent1].[CustomerID] = [Extent2].[CustomerID] 
       INNER JOIN [dbo].[DeviceModel] AS [Extent3] ON [Extent1].[DeviceModelID] = [Extent3].[DeviceModelID] 
       LEFT OUTER JOIN [dbo].[DeviceBrand] AS [Extent4] ON [Extent3].[BrandID] = [Extent4].[DeviceBrandID] 
       WHERE ([Extent1].[Status] = @p__linq__0) AND ([Extent1].[RelatedCompanyID] = @p__linq__1)) AS [Project2] 
      LEFT OUTER JOIN [dbo].[SystemUsers] AS [Extent6] ON [Project2].[C1] = [Extent6].[UserID] 
     ) AS [Project3]) AS [Project5] 
    LEFT OUTER JOIN [dbo].[SystemUsers] AS [Extent8] ON [Project5].[C1] = [Extent8].[UserID] 
) AS [Project6] 
ORDER BY [Project6].[JobOrderID] DESC 

ことを生成します。私は少し短いとよくパフォーマンスのクエリを作成するための助けが必要です。

Answer 1

まず、selectステートメントで使用している関係がクエリに含まれている（結合されている）よりも確実であることを確認してください。 SELECT文に基づいて、私はあなたのようなものを追加する必要があると思いますよね：

.Include("Customers").Include("DeviceModel").Include("AttendedStaff.SystemUsers") 

次へ]を、あなたは上のクエリを実行しているもの、すなわちStatusとRelatedCompanyID、インデックスフィールドでなければなりません。