Dataset Question

[PedroDePacos]

Hello,

I am updating an access database using a dataset. My question is... how come I can add a record to a table that doesn't have a primary key defined, but I cannot update a specified record? Here is the code that I am using...

 
            Dim cn As New OleDbConnection(AppSettings("cnString")) 
            Dim da As New OleDbDataAdapter("SELECT * FROM tblEmailAddresses", cn) 
            Dim ds As New DataSet() 
            Dim dv As DataView 
            Dim dr As DataRow 

            da.Fill(ds, "tblEmail") 
            'check if the customer's email has already been added 
            dv = ds.Tables("tblEmail").DefaultView 
            dv.RowFilter = "Email=" & "'" & strEmail & "'" 
            If dv.Count > 0 Then 
                'this email was already added 
                dv(0).Item("Promotions") = blnAgree 
                dv(0).Item("Name") = strName 
            Else 
                dr = ds.Tables("tblEmail").NewRow() 
                dr("Name") = strName 
                dr("Email") = strEmail 
                ds.Tables("tblEmail").Rows.Add(dr) 
            End If 

            'update the Email Address table in the database 
            cn.Open() 
            da.MissingSchemaAction = MissingSchemaAction.AddWithKey 
            Dim cmd As New OleDbCommandBuilder(da) 
            da.Update(ds, "tblEmail")

The above code works perfectly if a primary key is defined in the access table. I also tried substituting MissingSchemaAction.AddWithKey with MissingSchemaAction.Add and this didn't work either.

[DevGrp]

The DataAdapter uses a primary key to make updates. If you dont have a primary key, you can supply your own updating logic in a commandBuilder and pass it to the DataAdapter.