单项选择题 You create a Web Form that displays a GridView. The GridViews data source is a DataSet named dsOrders. The DataSet contains two DataTables named Orders and OrderDetails. You create a relation between the two DataTables using the following code segment. (Line numbers are included for reference only.)01 dtOrders = dsOrders.Tables[“Orders”]; 02 dtOrderDetails = dsOrders.Tables[“OrderDetail”]; 03 colParent = dtOrders.Columns[“OrderID”]; 04 colChild = dtOrderDetails.Columns[“ParentOrderID”]; 05 dsOrders.Relations.Add(“Rell”, colParent, colChild, false); You need to find the cause of the exception being raised in line 05. What should you do? （）

多项选择题 You are creating a Web Form. You write the following code segment to create a SqlCommand object. SqlConnection conn = new.SqlConnection(connString); conn.Open(); SqlCommand cmd = conn.CreateCommand(); cmd.CommandText = “select cont(*) from Customers”; You need to display the number of customers in the Customers table. Which two code segments can you use to achieve this goal? （）

单项选择题 You are transferring records from one database to another. You need to decide whether you can use the SqlBulkCopy class to transfer the records. What should you do? （）