Linq : Gettng T-Sql Squery With ToTraceString() method

We can use ObjectQuery.ToTraceString() to figure out what is going on behind the scenes. ToTraceString() returns the TSQL (assuming you are using the SQL Server provider) for that ObjectQuery.

Since we can see the TSQL code that EF generates I can poke around and figure what is going around behind the curtain.

For example if you ran this in LINQPad

void Main()
{
    PubsModel.pubsEntities context = new PubsModel.pubsEntities(EF_CONNECTION_STRING);

    // Entity SQL:
    // Returns ObjectQuery<T> directly
    ObjectQuery<author> esqlq = context.CreateQuery<author>(
        "SELECT VALUE a FROM authors AS a");
    esqlq.ToTraceString().Dump("--CreateQuery");
   
    // Linq to Entities
    // ObjectQuery<T> implements IQueryable<T>
    // This statement returns an ObjectQuery<T>
    // casted as IQueryable<T>
    IQueryable<author> linqq = from a in context.authors select a;   
    // So it must be cast back to execute ToTraceString()
    ((ObjectQuery)linqq).ToTraceString().Dump("--Linq Query");
}

You would get:

--CreateQuerySELECT [Extent1].[au_id] AS [au_id], [Extent1].[au_lname] AS [au_lname], [Extent1].[au_fname] AS [au_fname], [Extent1].[phone] AS [phone], [Extent1].[address] AS [address], [Extent1].[city] AS [city], [Extent1].[state] AS [state], [Extent1].[zip] AS [zip], [Extent1].[contract] AS [contract]
FROM [dbo].[authors] AS [Extent1]  --Linq QuerySELECT [Extent1].[au_id] AS [au_id], [Extent1].[au_lname] AS [au_lname], [Extent1].[au_fname] AS [au_fname], [Extent1].[phone] AS [phone], [Extent1].[address] AS [address], [Extent1].[city] AS [city], [Extent1].[state] AS [state], [Extent1].[zip] AS [zip], [Extent1].[contract] AS [contract]
FROM [dbo].[authors] AS [Extent1]