EF查询生成的SQL

在EF 4和EF 3.5 SP1中，我们可以使用ToTraceString()方法得到EF查询所生成的SQL。

 using (var context = new TestDBEntities())
 {
     var query = from p in context.Parents
                 where p.Name == "zhaokun"
                 select p;

     ObjectQuery<Parent> parents = query as ObjectQuery<Parent>;
     if (parents != null)
     {
         string sql = parents.ToTraceString();
     }
 }

totracestring

这里所生成的SQL为：

 [Extent1].[ParentID] AS [ParentID],
 [Extent1].[Name] AS [Name]
 FROM [dbo].[Parent] AS [Extent1]
 WHERE N'zhaokun'=[Extent1].[Name]

sqlone

在EF 4.1中，我们可以直接调用DbQuery<>的ToString()方法得到所生成的SQL。

 using (var context = new MyDbContext())
 {
     var people = from p in context.People
                  where p.PersonID >
                  select p;

     string sql = people.ToString();
 }

tostring

所生成的SQL是：

 SELECT
 [Extent1].[PersonID] AS [PersonID],
 [Extent1].[Name] AS [Name]
 FROM [dbo].[People] AS [Extent1]
 WHERE [Extent1].[PersonID] > 

sqltwo

这里的ToString()方法其实也就是调用了ObjectQuery<>的ToTraceString()方法。 DbQuery<>.ToString() ==>  System.Data.Entity.Internal.Linq.InternalQuery<>.ToString()方法，此方法 在.NET Reflector得到的实现是这样的：

 public override string ToString()
 {
     return this._objectQuery.ToTraceString();
 }

tostring（）

看书得到！