...
Dim AccessAdapter As New OleDbDataAdapter("SELECT * FROM T_Temp", AccessConn)
Dim dsAccess As New DataSet
Dim builder As New OleDbCommandBuilder(AccessAdapter)
accessAdapter.Fill(dsAccess, "T_Temp")
...
'ora importo dei dati da un csv 
...
Dim ExcelAdapter As New OleDbDataAdapter(cmd)
ExcelAdapter.Fill(dsAccess.Tables("T_Temp"))
ExcelConn.Close()
ExcelConn.Dispose()
ExcelAdapter.Dispose()

AccessConn.Open()
builder.GetUpdateCommand()
accessAdapter.Update(dsAccess, "T_Temp")