linq to sql duplicate select statements

**bruce barker** · Oct 30 '08, 05:45 AM

Re: linq to sql duplicate select statements

unlike an IEnumerable linq query, which walks the objects to produce the
query collection (the walk is done at query time), the linq to sql
query result is an expression parse tree. the parse tree is converted to
sql and excuted when you iterate the query. so you never want to iterate
(foreach) the query results more than once.

if you need to foreach more than once (say multiple binding), convert
the query to a list or array, which can be reused without rerunning the
query.

-- bruce (sqlwork.com)

jbot wrote:

I've got some pages that use linq to sql. When I look at the
generated sql statements in sql server profiler, I see the same
statements repeated. In the example below (from a linq data source
selected statement), the same sql query is run against the database 3
times at:
oStudent.Count
oStudent(0).lkp status.students tatus
oStudent(0).lkp status.statusca tegory
>
Is this the expected behavior? I expected the select to be run only
once. Thanks in advance for help with this.
>
Private Sub lds_Student_Sel ected(ByVal sender As Object, ByVal e As
System.Web.UI.W ebControls.Linq DataSourceStatu sEventArgs) Handles
lds_Student.Sel ected
>
Dim oStudent As List(Of personal) = CType(e.Result, List(Of
personal))
If oStudent.Count = 1 Then
Session("Curren tStudentStatus" ) =
oStudent(0).lkp status.students tatus
Session("Curren tStudentStatusC ategory") =
oStudent(0).lkp status.statusca tegory
End If
End Sub
>
Jim

linq to sql duplicate select statements

linq to sql duplicate select statements

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