Question

我有以下linq查询（false和true是因为动态创建查询）：

(from x in ((ObjectQuery<PersonView>)PersonView).MergeAs(0)
where x.Info && (((False || (True && (x.Person.FirstName == compareValue))) || (True && (x.Person.FirstName == compareValue))) || (True &&     ((x.Person.FirstName == "") || (x.Person.FirstName == null))))
where (x.DateTime >= startDate.Date) && (x.DateTime <= endDate.Date)
select x.PersonID).Distinct()

它转换为这个SQL查询：

SELECT 
[Distinct1].[PersonID] AS [PersonID]
FROM ( SELECT DISTINCT 
    [Extent1].[PersonID] AS [PersonID]
    FROM  (SELECT 
           [PersonView].[PersonID] AS [PersonID], 
           [PersonView].[DateTime] AS [DateTime], 
           [PersonView].[Info]     AS     [Info]
           FROM [core].[PersonView] AS     [PersonView]) AS [Extent1]
           LEFT OUTER JOIN [core].[Persons] AS [Extent2] ON [Extent1].[PersonID] = [Extent2].[PersonID]
           WHERE ([Extent1].[Info] = 1) AND ([Extent2].[FirstName] IN (@p__linq__0,@p__linq__1,N'') OR [Extent2].[FirstName] IS NULL) AND ([Extent1].[DateTime] >= @p__linq__2) AND ([Extent1].[DateTime] <= @p__linq__3)
)  AS [Distinct1]

我的目标是因为性能而将内部联接替换为左联接。我一直在搜索，我已经读过，如果该属性不可为空（在这种情况下的人不可为空），它应该被转换为内连接。这显然不是这种情况。如何让Entity Framework生成内部联接？

编辑：Here说明必需的关联应转换为内部联接。什么使它成为必需的关联？在我的情况下，外键不可为空。

我先工作数据库。这就是生成的内容：

public partial class PersonView: DbEntity
{    
    private int _personID;
    private System.DateTime _dateTime;
    private bool _info;
    public int PersonID { get{ return _personID;} set{ _personID = value; OnPropertyChanged("PersonID");} }
    public System.DateTime DateTime { get{ return _dateTime;} set{ _dateTime = value; OnPropertyChanged("DateTime");} }
    public bool Info{ get{ return _info;} set{ _info = value; OnPropertyChanged("Info");} }

    public virtual Person Person { get; set; }
}

我尝试添加元数据，但没有区别。

[MetadataType(typeof(PersonViewMetaData))]
public partial class PersonView
{    }
public sealed class PersonViewMetaData
{
  [Required]
  public Person Person { get; set; }
}

具有非可空导航属性的Linq查询转换为左连接

0 个答案: