Question

I use EF 5 for my project and im profilin it with EntityProfiler and i see that sql that is generated whene i use Find for the query is:

SELECT TOP (2) [Extent1].[ID]                  AS [ID],
               [Extent1].[TargetID]            AS [TargetID],
               [Extent1].[BranchID]            AS [BranchID],
               [Extent1].[ApplicationStatus]   AS [ApplicationStatus],
               [Extent1].[UserID]              AS [UserID],
               [Extent1].[AssignedOfficer]     AS [AssignedOfficer],
               [Extent1].[AssignedOfficerCRM]  AS [AssignedOfficerCRM],
               [Extent1].[RegistrationDate]    AS [RegistrationDate],
               [Extent1].[DecisionReasons]     AS [DecisionReasons],
               [Extent1].[DecisionExceptionID] AS [DecisionExceptionID],
               [Extent1].[RiskComment]         AS [RiskComment],
               [Extent1].[CESInformed]         AS [CESInformed],
               [Extent1].[IsCommited]          AS [IsCommited]
FROM   [dbo].[Applications] AS [Extent1]
WHERE  [Extent1].[ID] = '900100' /* @p0 */

Code that is called is:

 public T GetByID(object primaryKey)
        {
            return DB.Set<T>().Find(primaryKey);
        }

so my questin is why in sql that is generated is Select Top (2)

Answer 1

It executes Select Top (2) cause the DBSet uses internally SingleOrDefault() (see here method FindInStore) for the Find method to execute the query.

This ensures, that if 2 results are returned, an exception is thrown, cause SingleOrDefault defines that it expects exactly one result or nothing.

Select Top (1) is generated as Sql wenn you use FirstOrDefault().