ASP.NET Tutorial/ADO.net Database/Transaction
Содержание
- 1 Execute database commands within a single local transaction. You can test rollback and partial rollback.
- 2 Click this button to display current data.
- 3 Click this button to execute a transaction
- 4 Click this button to restore the original state of data
- 5 Use transaction to group operations (VB.net)
Execute database commands within a single local transaction. You can test rollback and partial rollback.
<source lang="csharp">
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="Default"%> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server">
<title>Begin Local Transactions</title>
</head> <body>
<form id="form1" runat="server">
Click this button to display current data.
<asp:Button id="ShowButton" runat="server" Text="Show Data" OnClick="ShowButton_Click"></asp:Button>
Click this button to execute a transaction
<asp:Button id="ExecuteButton" runat="server" Text="Execute Transaction" OnClick="ExecuteButton_Click"></asp:Button>
<asp:CheckBox id="CheckBox_Partial" runat="server" Text="Partial Rollback"></asp:CheckBox>
Click this button to restore the original state of data
<asp:Button id="RestoreButton" runat="server" Text="Restore" OnClick="RestoreButton_Click"></asp:Button>
<asp:Label runat="server" id="lblMessage" />
<asp:DataGrid id="grid" runat="server" visible="False" CellPadding="4" GridLines="None" ForeColor="#333333" CssClass="shadowed" font-size="X-Small" font-names="verdana">
<AlternatingItemStyle BackColor="White" />
<ItemStyle BackColor="#EFF3FB" />
<HeaderStyle ForeColor="White" BackColor="#507CD1" Font-Bold="True" />
<FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<EditItemStyle BackColor="#2461BF" />
<SelectedItemStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
<PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
</asp:DataGrid>
</form>
</body> </html> File: Default.aspx.cs using System; using System.Data; using System.Data.SqlClient; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; public partial class Default : System.Web.UI.Page {
private const string ConnString = "SERVER=(local);DATABASE=northwind;Trusted_Connection=yes;";
private const string SelectCmd = "SELECT employeeid, firstname, lastname FROM Employees";
private const string UpdateCmd = "UPDATE Employees SET firstname="Michela" WHERE EmployeeID=1";
private const string InsertCmd = "INSERT INTO Employees (firstname,lastname) VALUES ("Dino", "Esposito")";
protected void ShowButton_Click(object sender, EventArgs e)
{
using (SqlConnection conn = new SqlConnection(ConnString))
{
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.rumandText = SelectCmd;
conn.Open();
grid.DataSource = cmd.ExecuteReader();
grid.DataBind();
grid.Visible = true;
conn.Close();
}
}
protected void ExecuteButton_Click(object sender, EventArgs e)
{
using (SqlConnection conn = new SqlConnection(ConnString))
{
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
conn.Open();
SqlTransaction t = conn.BeginTransaction();
cmd.Transaction = t;
try
{
cmd.rumandText = UpdateCmd;
cmd.ExecuteNonQuery();
t.Save("AfterUpdate");
cmd.rumandText = InsertCmd;
cmd.ExecuteNonQuery();
if (CheckBox_Partial.Checked)
t.Rollback("AfterUpdate");
t.rumit();
lblMessage.Text = "Done";
grid.Visible = false;
}
catch (Exception exc)
{
t.Rollback();
lblMessage.Text = "Error occurred: " + exc.Message;
}
}
}
protected void RestoreButton_Click(object sender, EventArgs e) {
using (SqlConnection conn = new SqlConnection(ConnString)) {
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
conn.Open();
SqlTransaction t = conn.BeginTransaction();
cmd.Transaction = t;
try {
cmd.rumandText = "UPDATE Employees SET firstname="Nancy" WHERE EmployeeID=1";
cmd.ExecuteNonQuery();
cmd.rumandText = "DELETE FROM Employees WHERE EmployeeID >9";
cmd.ExecuteNonQuery();
t.rumit();
lblMessage.Text = "Done";
grid.Visible = false;
}
catch (Exception exc)
{
t.Rollback();
lblMessage.Text = "Error occurred: " + exc.Message;
}
}
}
}</source>
Use transaction to group operations (VB.net)
<source lang="csharp">
<%@ Page Language="VB" %> <%@ Import Namespace="System.Data" %> <%@ Import Namespace="System.Data.OleDb" %> <script runat="server">
"declare connection
dim Conn as new OleDbConnection( _
"PROVIDER=Microsoft.Jet.OLEDB.4.0;" _
& "DATA SOURCE=" _
& Server.MapPath("EmployeeDatabase.mdb;"))
sub Page_Load(Sender as Object, e as EventArgs)
dim objTrans as OleDbTransaction
dim objCmd as OleDbCommand = new OleDbCommand _
("DELETE from employee where UserID = 32", Conn)
Conn.Open()
objTrans = Conn.BeginTransaction()
objCmd.Transaction = objTrans
try
objCmd.rumandText = "INSERT INTO employee " & _
"(ID, FirstName, LastName) VALUES " & _
"(109, "J", "S")"
objCmd.ExecuteNonQuery()
objCmd.rumandText = "INSERT INTO employee " & _
"(ID, FirstName, LastName) VALUES " & _
"(119, "J", "S")"
objCmd.ExecuteNonQuery()
objTrans.rumit()
Label1.Text = "Both operations performed successfully"
catch ex as OleDbException
objTrans.RollBack()
Label1.Text = ex.Message & ""
Label1.Text = "Both operations failed"
finally
objCmd.Connection.Close()
end try
end sub
</script> <html><body>
<form runat="server">
<asp:Label id="Label1" runat="server"
maintainstate=false />
</form>
</body></html></source>
