Legge da due Command i primi 2 record

Imports System
Imports System.Data
Imports System.Data.SqlClient

Module Module1
Sub Main()
Dim myconnection1, myconnection2 As SqlConnection
Dim mycommand1, mycommand2 As SqlCommand
Dim mytransaction1, mytransaction2 As SqlTransaction
Dim myreader As SqlDataReader
Dim ConnectionString As String

'open a database connection

ConnectionString = "Data Source=(local);Initial Catalog=Northwind;Integrated Security=SSPI;"
myconnection1 = New SqlConnection(ConnectionString)
myconnection2 = New SqlConnection(ConnectionString)

Try
myconnection1.Open()
myconnection2.Open()

'start a transaction

mytransaction1 = myconnection1.BeginTransaction()
mytransaction2 = myconnection2.BeginTransaction(IsolationLevel.ReadUncommitted)

'configure command object to use transaction

mycommand1 = New SqlCommand()
mycommand1.Connection = myconnection1
mycommand1.Transaction = mytransaction1

mycommand2 = New SqlCommand()
mycommand2.Connection = myconnection2
mycommand2.Transaction = mytransaction2

'execute various sql statements


mycommand1.CommandText = "insert into orders default values"
mycommand1.ExecuteNonQuery()
mycommand1.CommandText = "insert into orders default values"
mycommand1.ExecuteNonQuery()

mycommand2.CommandText = "select top 2 orderid from orders order by orderid desc"
myreader = mycommand2.ExecuteReader()
Console.WriteLine("Last 2 Orders - Transaction is pending")
Console.WriteLine("======================================")
While myreader.Read()
Console.WriteLine(myreader.GetInt32(0))
End While
myreader.Close()
Console.ReadLine()

mytransaction1.Rollback()
mycommand2.CommandText = "select top 2 orderid from orders order by orderid desc"
myreader = mycommand2.ExecuteReader()

Console.WriteLine("Last 2 Orders - Transaction rolled back")
Console.WriteLine("=======================================")
While myreader.Read()
Console.WriteLine(myreader.GetInt32(0))
End While
Console.ReadLine()
Catch e As Exception
Console.WriteLine(e.Message)
Console.ReadLine()
Finally
myconnection1.Close()
myconnection2.Close()
End Try
End Sub
End Module