Question

此代码块从数据库收集作业顺序信息，将表连接在一起，并返回一个对象。那么一切都像魅力一样，但太慢了？

这是完成工作的代码;

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;
}

这个块产生了那么长的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

好吧，我无法判断长期查询是否合适。我需要帮助才能创建一些更短且性能更好的查询。

Answer 1

首先要确保在您的查询中包含（加入）您在select语句中使用的任何关系。根据你的select语句，我猜你需要添加类似的东西：

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

接下来，您要查询的任何内容都应该是一个索引字段，即Status和RelatedCompanyID。

如何使用EF创建更短的查询？

1 个答案: