Question

I’m working in ASP.NET ( beginner ) and I tried to make update query using the code below. I try the same code to get date from database and it work fine, but only don’t work with update query.

Note: I use LINQ

Dim updateCust = (From cust In db.Customers 
                  Where cust.CustomerID = "JILLF").ToList()(0)

updateCust.ContactName = "Jill Shrader"

Try
    db.SubmitChanges()
Catch
    ' Handle exception.
End Try

RefreshData()

I got this code from : http://msdn.microsoft.com/en-us/library/bb907191.aspx

Should I change something in my SQL server 2008 so I could use update option ?

Answer 1

The problem is that you are converting your results into a List and then take first element. You’ll get the data but it is not bound to database any more. I believe something like this would work:

Dim updateCust = (From cust In db.Customers 
                  Where cust.CustomerID = "JILLF").FirstOrDefault()

If updateCust IsNot Nothing Then
    updateCust.ContactName = "Jill Shrader"
End If

db.SubmitChanges()

EDIT

Although FirstOrDefault() would work fine here you may want to use SingleOrDefault() which would throw an exception if there were more than one record with the same CustomerID (or broadly, more records returned). I assume that this column is a primary key column (it looks like it) and that guarantees row uniqueness.