How do I validate the data in database with what is to be saved through the textbox

Question

Hi Team how can validate a data which has be stored into the database with the data which is stored through the text box in c#. i want when the user try to save a data which already in the database should give the user an error that the data is already captured. Please Correct For Me the Below Code: Here c# code: using System; using System.Collections; using System.Configuration; using System.Data; using System.Data.Odbc; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; public partial class station : System.Web.UI.Page { string str; int count; protected void Page_Load(object sender EventArgs e) { } protected void Btnsave_Click(object sender EventArgs e) { if (street_name != txtstreetname.Text) { if (System.Windows.Forms.MessageBox.Show(The Street Name Is Already Captured! Error! System.Windows.Forms.MessageBoxButtons.RetryCancel System.Windows.Forms.MessageBoxIcon.Error) == System.Windows.Forms.DialogResult.Retry) Response.Redirect(station.aspx); } try { OdbcCommand cmd; OdbcConnection conn = new OdbcConnection(dsn=parcel;uid=dba;pwd=sql); cmd = new OdbcCommand(insert into tbl_street(Route_codeRouteStation) values (' + txtstreetcode.Text + '' + Txtstreet.Text + '' + txtstation.Text + ') conn); if (System.Windows.Forms.MessageBox.Show(confrim The Data Prompt System.Windows.Forms.MessageBoxButtons.YesNo System.Windows.Forms.MessageBoxIcon.Question) == System.Windows.Forms.DialogResult.Yes) conn.Open(); cmd.ExecuteNonQuery(); conn.Close(); if (System.Windows.Forms.MessageBox.Show(save Successfully prompt System.Windows.Forms.MessageBoxButtons.YesNo System.Windows.Forms.MessageBoxIcon.Information) == System.Windows.Forms.DialogResult.Yes) Response.Redirect(station.aspx); } catch (Exception) { Response.Redirect(station.aspx); } } Regard George

Satyapriya Nayak · Answer

Hi George Try this... Normal 0 Table creation create table employee (eid int primary key identityename varchar(50)eaddress varchar(50)) @ Page Language =C# AutoEventWireup =true CodeBehind =Default.aspx.cs Inherits =Insert_data_ifnot_exits._Default %> DOCTYPE html PUBLIC -//W3C//DTD XHTML 1.0 Transitional//EN http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd> html xmlns =http://www.w3.org/1999/xhtml > head runat =server> title > Untitled Page title > head > body > form id =form1 runat =server> div > div > asp : Button ID =Button1 runat =server Text =Availability of name from the database BackColor =#FF99FF Font-Bold =True Width =329px onclick =Button1_Click /> br /> asp : Label ID =Labelcheck Text =Ename runat =server BackColor =#FFFF99 Width =197px ForeColor =#FF3300> asp : Label > asp : TextBox ID =txtUserName runat =server Width =197px> asp : TextBox > asp : RequiredFieldValidator ID =RequiredFieldValidator1 runat =server ControlToValidate =txtUserName ErrorMessage =*Name Required> asp : RequiredFieldValidator > br /> asp : Label ID =Label1 Text =Eaddress runat =server BackColor =#FFFF99 Width =197px ForeColor =#FF3300> asp : Label > asp : TextBox ID =txtUserAddress runat =server Width =197px> asp : TextBox > asp : RequiredFieldValidator ID =RequiredFieldValidator2 runat =server ControlToValidate =txtUserAddress ErrorMessage =*Address Required> asp : RequiredFieldValidator > br /> asp : Label ID =lblMessage runat =server BackColor =#FF3300 ForeColor =Black> asp : Label > form > body > html > using System; using System.Collections; using System.Configuration; using System.Data; using System.Linq; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Xml.Linq; using System.Data.SqlClient; namespace Insert_data_ifnot_exits { public partial class _Default : System.Web.UI. Page { string connStr = ConfigurationManager .ConnectionStrings[ ConnectionString ].ConnectionString; SqlCommand com; string str = null ; protected void Button1_Click( object sender EventArgs e) { namecheck(); } public void namecheck() { SqlConnection con = new SqlConnection (connStr); con.Open(); str = select count(*)from employee where ename=' + txtUserName.Text + ' ; com = new SqlCommand (str con); int count = Convert .ToInt32(com.ExecuteScalar()); con.Close(); if (count > 0) { lblMessage.Text = Sorry! you can't take this username ; } else { lblMessage.Text = You can take this username ; con.Open(); str = insert into employee(enameeaddress) values(' + txtUserName.Text + '' + txtUserAddress.Text + ') ; com = new SqlCommand (str con); com.ExecuteNonQuery(); con.Close(); } } } } Thanks

Santhosh Kumar Jayaraman · Answer

We can do it in 2 ways. In Btnsave_click 1.Query the table with where clause like select * from tbl_Street where streetcode=streetcode if it returns any rows then the street already exists then display warning message else execute insert query 2. The other way to do this is create a stored proc and pass the street code as parameter. inside sp check whether the field already exists then return some integer(say 2) then do the rest of the things like aboveif it successfully inserted return another integer(1). Here in code check the return value if 1 display user that successfully saved else if its 2 display the error message.