在域服务类和实体数据模型中使用Linq查询SQL视图

Visual Studio 2008 | Silverlight 3 | SQL Server 2005 |域服务类|实体数据模型

我有一个数据库表“Students”，其中有列FirstName、LastName、Semmer、ProgramOfStudy、Column等

目标是根据给定的学期和学习计划中所有学生的姓氏首字母，返回一个总数（按姓氏首字母分组的学生人数）

我没有成功地编写LINQ查询，我想尝试使用SQL视图

创建视图（17000行分组到5000行）

视图由“LastNameStartsWith”、“Total”、“AcademicPeriod”、“ProgramCode”组成

将视图添加到.edmx模型中

编写了以下查询

作为林克

public IQueryable GetVw_studentAlphabetSet(int cycleID, string progCode)
     {
          var query = from s in db.vw_studentAlphabetSet
          where ((s.programCode == progCode) && (s.academicPeriod == cycleID))
          select s;
          return query; 
}

当以sql形式运行并在MSSMS中填充参数时，视图将过滤到25行，以报告发生次数。A-Z，不报告X，因为没有以X开头的姓氏

如果在返回查询上设置了断点；，它正确地报告了24个实体计数，但每个实体都是相同的。lastnamestartswith='A'，总计=21

因此，似乎过滤正在工作，但有一个bug。每个实体都应该是唯一的A-Z

如果我把它加进去，你喜欢在哪里

where (s.programCode == progCode) && (s.academicPeriod == cycleID) && (s.LastNameStartsWith == "B");

生成正确的返回。B、 35200890，BSED-ELED-ED

当使用Linq返回元素时，我得到一个微不足道的元素来使用。LastNameStartsWith=“A”，总计=21。但是同样的，B-Z和总数没有返回。在DomainServices类中，它确实报告了元素计数为24。他们都去了哪里。我本应该多得到23个元素，即使他们都报告A和21

那么，在使用视图和Linq时，您是否应该知道一些特别的事情

这里是实体模型的设计器

[assembly: global::System.Data.Objects.DataClasses.EdmSchemaAttribute()]

// Original file name:
// Generation date: 2/21/2010 10:25:00 PM
namespace sproc.Web
{

    /// 
    /// There are no comments for GLADYS_2010Entities in the schema.
    /// 
    public partial class GLADYS_2010Entities : global::System.Data.Objects.ObjectContext
    {
        /// 
        /// Initializes a new GLADYS_2010Entities object using the connection string found in the 'GLADYS_2010Entities' section of the application configuration file.
        /// 
        public GLADYS_2010Entities() : 
                base("name=GLADYS_2010Entities", "GLADYS_2010Entities")
        {
            this.OnContextCreated();
        }
        /// 
        /// Initialize a new GLADYS_2010Entities object.
        /// 
        public GLADYS_2010Entities(string connectionString) : 
                base(connectionString, "GLADYS_2010Entities")
        {
            this.OnContextCreated();
        }
        /// 
        /// Initialize a new GLADYS_2010Entities object.
        /// 
        public GLADYS_2010Entities(global::System.Data.EntityClient.EntityConnection connection) : 
                base(connection, "GLADYS_2010Entities")
        {
            this.OnContextCreated();
        }
        partial void OnContextCreated();
        /// 
        /// There are no comments for vw_studentAlphabet in the schema.
        /// 
        public global::System.Data.Objects.ObjectQuery vw_studentAlphabet
        {
            get
            {
                if ((this._vw_studentAlphabet == null))
                {
                    this._vw_studentAlphabet = base.CreateQuery("[vw_studentAlphabet]");
                }
                return this._vw_studentAlphabet;
            }
        }
        private global::System.Data.Objects.ObjectQuery _vw_studentAlphabet;
        /// 
        /// There are no comments for vw_studentAlphabet in the schema.
        /// 
        public void AddTovw_studentAlphabet(vw_studentAlphabet vw_studentAlphabet)
        {
            base.AddObject("vw_studentAlphabet", vw_studentAlphabet);
        }
    }
    /// 
    /// There are no comments for GLADYS_2010Model.vw_studentAlphabet in the schema.
    /// 
    /// 
    /// academicPeriod
    /// programCode
    /// 
    [global::System.Data.Objects.DataClasses.EdmEntityTypeAttribute(NamespaceName="GLADYS_2010Model", Name="vw_studentAlphabet")]
    [global::System.Runtime.Serialization.DataContractAttribute(IsReference=true)]
    [global::System.Serializable()]
    public partial class vw_studentAlphabet : global::System.Data.Objects.DataClasses.EntityObject
    {
        /// 
        /// Create a new vw_studentAlphabet object.
        /// 
        /// Initial value of academicPeriod.
        /// Initial value of programCode.
        public static vw_studentAlphabet Createvw_studentAlphabet(int academicPeriod, string programCode)
        {
            vw_studentAlphabet vw_studentAlphabet = new vw_studentAlphabet();
            vw_studentAlphabet.academicPeriod = academicPeriod;
            vw_studentAlphabet.programCode = programCode;
            return vw_studentAlphabet;
        }
        /// 
        /// There are no comments for Property LastNameStartsWith in the schema.
        /// 
        [global::System.Data.Objects.DataClasses.EdmScalarPropertyAttribute()]
        [global::System.Runtime.Serialization.DataMemberAttribute()]
        public string LastNameStartsWith
        {
            get
            {
                return this._LastNameStartsWith;
            }
            set
            {
                this.OnLastNameStartsWithChanging(value);
                this.ReportPropertyChanging("LastNameStartsWith");
                this._LastNameStartsWith = global::System.Data.Objects.DataClasses.StructuralObject.SetValidValue(value, true);
                this.ReportPropertyChanged("LastNameStartsWith");
                this.OnLastNameStartsWithChanged();
            }
        }
        private string _LastNameStartsWith;
        partial void OnLastNameStartsWithChanging(string value);
        partial void OnLastNameStartsWithChanged();
        /// 
        /// There are no comments for Property Total in the schema.
        /// 
        [global::System.Data.Objects.DataClasses.EdmScalarPropertyAttribute()]
        [global::System.Runtime.Serialization.DataMemberAttribute()]
        public global::System.Nullable Total
        {
            get
            {
                return this._Total;
            }
            set
            {
                this.OnTotalChanging(value);
                this.ReportPropertyChanging("Total");
                this._Total = global::System.Data.Objects.DataClasses.StructuralObject.SetValidValue(value);
                this.ReportPropertyChanged("Total");
                this.OnTotalChanged();
            }
        }
        private global::System.Nullable _Total;
        partial void OnTotalChanging(global::System.Nullable value);
        partial void OnTotalChanged();
        /// 
        /// There are no comments for Property academicPeriod in the schema.
        /// 
        [global::System.Data.Objects.DataClasses.EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)]
        [global::System.Runtime.Serialization.DataMemberAttribute()]
        public int academicPeriod
        {
            get
            {
                return this._academicPeriod;
            }
            set
            {
                this.OnacademicPeriodChanging(value);
                this.ReportPropertyChanging("academicPeriod");
                this._academicPeriod = global::System.Data.Objects.DataClasses.StructuralObject.SetValidValue(value);
                this.ReportPropertyChanged("academicPeriod");
                this.OnacademicPeriodChanged();
            }
        }
        private int _academicPeriod;
        partial void OnacademicPeriodChanging(int value);
        partial void OnacademicPeriodChanged();
        /// 
        /// There are no comments for Property programCode in the schema.
        /// 
        [global::System.Data.Objects.DataClasses.EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)]
        [global::System.Runtime.Serialization.DataMemberAttribute()]
        public string programCode
        {
            get
            {
                return this._programCode;
            }
            set
            {
                this.OnprogramCodeChanging(value);
                this.ReportPropertyChanging("programCode");
                this._programCode = global::System.Data.Objects.DataClasses.StructuralObject.SetValidValue(value, false);
                this.ReportPropertyChanged("programCode");
                this.OnprogramCodeChanged();
            }
        }
        private string _programCode;
        partial void OnprogramCodeChanging(string value);
        partial void OnprogramCodeChanged();
    }
}

下面是调用域服务和实体模型的客户端代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Ria.Data;
using GLADYS.Web.GladysDataLayers;
using GLADYS.Web.GladysServices;


namespace GLADYS
    {
    public partial class uc_AlphabetFilter : UserControl
        {

        //data context for getting the data through the ria service.
        private dscStudents ctx = new dscStudents();




        public uc_AlphabetFilter()
            {
            InitializeComponent();
            //Loaded += new RoutedEventHandler(uc_AlphabetFilter_Loaded);
            ctx.Load(ctx.GetVw_studentAlphabetSetQuery(200980, "BSED-ELED-ED")).Completed += new EventHandler(uc_AlphabetFilter_Completed);            
            }





        void uc_AlphabetFilter_Completed(object sender, EventArgs e)
            {
            foreach (var q in ctx.vw_studentAlphabets)
                {
                uc_AlphaButton btn = new uc_AlphaButton();
                btn.pAlphaLetter = q.LastNameStartsWith;
                btn.PNumber = q.Total.Value;

                myWrapPanel.Children.Add(btn);
                }
            }

---

同样的问题也会被问到，但方法不同。

使用实体框架处理视图时，请确保正确设置了实体键。这一点经常被忽略，因为视图没有主键，EF试图推断主键，而这通常是不正确的。具有不正确的实体键可能会导致不一致和奇怪的查询结果。

请向我们展示该视图的csdl、ssdl和映射，好吗？也许设计师在那里搞砸了。kubal5003，我添加了客户端代码和服务器端EDMX设计器代码。我真的希望你能看到一些东西。在我关于这个问题的另一篇文章中，它与LINQtoSQL和WCF服务一起工作得非常好。我不是真的想中途换马，只是想确保我没有发疯。