內連接和實體框架外連接選項4.0

我使用EF 4.0和我需要一個內部聯接，並用N外部連接我就開始實施這一使用不同的方法，但陷入困境的一些點來實現查詢。內連接和實體框架外連接選項4.0

下面是兩個例子，我怎麼開始做這個使用ObjectQuery<'T'> and Linq to Entity

1）使用ObjectQuery<'T'>我實現靈活的外部連接的，但我不知道如何執行在這種情況下，實體規則內連接（默認情況下包括（「辦法」）做外連接，但我需要通過內部編號加入）。

public static IEnumerable<Race> GetRace(List<string> includes, DateTime date) 
    { 
     IRepository repository = new Repository(new BEntities()); 

     ObjectQuery<Race> result = (ObjectQuery<Race>)repository.AsQueryable<Race>(); 

     //perform outer joins with related entities 
     if (includes != null)     
      foreach (string include in includes) 
       result = result.Include(include); 


     //here i need inner join insteard of default outer join 
     result = result.Include("Rules"); 

     return result.ToList(); 
    }

2）使用LINQ to實體，我需要有一種外（在GetRace（事端等））加入其中，我可以通過與實體清單包括），也是我需要執行正確的內部連接用實體規則

public static IEnumerable<Race> GetRace2(List<string> includes, DateTime date) 
    { 
     IRepository repository = new Repository(new BEntities()); 

     IEnumerable<Race> result = from o in repository.AsQueryable<Race>() 
            from b in o.RaceBetRules 
            select new 
            { 
            o 
            }); 

     //I need here: 
     // 1. to perform the same way inner joins with related entities like with ObjectQuery above 

     //here i getting List<AnonymousType> which i cant cast to 
     //IEnumerable<Race> when i did try to cast like 
     //(IEnumerable<Race>)result.ToList(); i did get error: 
     //Unable to cast object of type 
     //'System.Collections.Generic.List`1[<>f__AnonymousType0`1[BetsTipster.Entity.Tip.Types.Race]]' 
     //to type 
     //'System.Collections.Generic.IEnumerable`1[BetsTipster.Entity.Tip.Types.Race]'. 
     return result.ToList(); 
    }

可能有人對此有一些想法。

來源

2010-09-01 Kuncevic

public static IEnumerable<Race> GetRace(List<string> includes, DateTime date) 
    { 
     IRepository repository = new Repository(new BEntities()); 

     ObjectQuery<Race> result = (ObjectQuery<Race>)repository.AsQueryable<Race>(); 

     //perform outer joins with related entities 
     if (includes != null) 
      foreach (string include in includes) 
       result = result.Include(include); 


     //Perform inner join with "Rules" table 
     result = (ObjectQuery<Race>)result.Include("Rules").Where(x => x.RaceBetRules.Any()); 

     result = (ObjectQuery<Race>)result.OrderBy(x => x.RaceDate); 


     return result.ToList(); 
    }

來源

2011-01-09 04:46:59 Kuncevic

這裏是一個post處理內部聯接在LINQ到實體。
希望這將在正確的方向指向你。

來源

2010-09-02 12:21:41 Devart

內連接和實體框架外連接選項4.0

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