When using Update, the order of execution is as follows:

1. The values in the DataRow are moved to the parameter values.
2. The OnRowUpdating event is raised.
3. The command executes.
4. If the command is set to FirstReturnedRecord, then the first returned result is placed in the DataRow.
5. If there are output parameters, they are placed in the DataRow.
6. The OnRowUpdated event is raised.
7. AcceptChanges is called.

Private Sub DemonstrateRowState()
    'Run a function to create a DataTable with one column.
    Dim dataTable As DataTable = MakeTable()
    Dim dataRow As DataRow

    ' Create a new DataRow.
    dataRow = dataTable.NewRow()
    ' Detached row.
    Console.WriteLine(String.Format("New Row {0}", dataRow.RowState))

    dataTable.Rows.Add(dataRow)
    ' New row.
    Console.WriteLine(String.Format("AddRow {0}", dataRow.RowState))

    dataTable.AcceptChanges()
    ' Unchanged row.
    Console.WriteLine(String.Format("AcceptChanges {0}", dataRow.RowState))

    dataRow("FirstName") = "Scott"
    ' Modified row.
    Console.WriteLine(String.Format("Modified {0}", dataRow.RowState))

    dataRow.Delete()
    ' Deleted row.
    Console.WriteLine(String.Format("Deleted {0}", dataRow.RowState))
End Sub

Private Function MakeTable() As DataTable
    ' Make a simple table with one column.
    Dim dt As New DataTable("dataTable")
    Dim firstName As New DataColumn("FirstName", _
       Type.GetType("System.String"))
    dt.Columns.Add(firstName)
    Return dt
End Function

Private Sub DemonstrateRowState()
    'Run a function to create a DataTable with one column.
    Dim dataTable As DataTable = MakeTable()
    Dim dataRow As DataRow

    ' Create a new DataRow.
    dataRow = dataTable.NewRow()
    ' Detached row.
    Console.WriteLine(String.Format("New Row {0}", dataRow.RowState))

    dataTable.Rows.Add(dataRow)
    ' New row.
    Console.WriteLine(String.Format("AddRow {0}", dataRow.RowState))

    dataTable.AcceptChanges()
    ' Unchanged row.
    Console.WriteLine(String.Format("AcceptChanges {0}", dataRow.RowState))

    dataRow("FirstName") = "Scott"
    ' Modified row.
    Console.WriteLine(String.Format("Modified {0}", dataRow.RowState))

    dataRow.Delete()
    ' Deleted row.
    Console.WriteLine(String.Format("Deleted {0}", dataRow.RowState))
End Sub

Private Function MakeTable() As DataTable
    ' Make a simple table with one column.
    Dim dt As New DataTable("dataTable")
    Dim firstName As New DataColumn("FirstName", _
       Type.GetType("System.String"))
    dt.Columns.Add(firstName)
    Return dt
End Function

reate table TestTable (id int primary key, fname nvarchar(50), lname nvarchar(50))

insert into TestTable values (1, 'Mike', 'Spike')

insert into TestTable values (2, 'John', 'Johnson')

insert into TestTable values (3, 'Pete', 'Peterson')

--drop table TestTable

Then create a new C# Console application and run the following code:

        static void Main(string[] args)

        {

            string cs = @"Data Source=<your server>;Initial Catalog=<your database>;Integrated Security=SSPI";

            string sql = "SELECT id, fname, lname FROM TestTable";

            using (SqlConnection con = new SqlConnection(cs))

            {

                SqlDataAdapter da = new SqlDataAdapter(sql, con);

                DataTable dt = new DataTable("Persons");

                da.Fill(dt);

                Console.WriteLine("Rows are untouched...");

                ViewDataTableRowStatus(dt);

                // Modify a row.

                Console.WriteLine("Modifying the first row...");

                dt.Rows[0][1] = "Jake";

                ViewDataTableRowStatus(dt);

                // Add a row.

                Console.WriteLine("Adding a row");

                dt.Rows.Add(new object[]{100, "Paul", "Paulson..."});

                ViewDataTableRowStatus(dt);

                // Now, if calling AcceptChanges() all rows will be set to Unchanged.

                Console.WriteLine("Calling AcceptChanges()...");

                dt.AcceptChanges();

                ViewDataTableRowStatus(dt);

                // This means that when we call update on the DataAdapter, it will return 0

                // since no rows has actuall been sent to the database. (first we need to build the INSERT and UPDATE commands)

                SqlCommandBuilder builder = new SqlCommandBuilder(da);

                da.InsertCommand = builder.GetInsertCommand();

                da.UpdateCommand = builder.GetUpdateCommand();

                int rows = da.Update(dt);

                Console.WriteLine("Updated rows: {0}", rows);

            }

        }

        private static void ViewDataTableRowStatus(DataTable dt)

        {

            foreach (DataRow dr in dt.Rows)

            {

                Console.WriteLine("Id:{0}\tFirstName: {1}\tRowState: {2}", dr[0].ToString(), dr[1].ToString(), dr.RowState.ToString());

            }

            Console.WriteLine();

        }