it shouldnt accept similar values

  i want to enter value from text box to database .. but what i will do with which it doesn't accept similar value...
for ex: i have already entered a value name column david but when i trying to enter the similar value , it shouldn't accept that value and show an msg box that there is an error....

plz answer ....
  and answer my previous question also....

Hi David,
Here is a sample stored procedure that checks if the City exists already in database and returns the result. The same can be done for your textbox value. You can execute the stored proc and read the data in your data access layer which in turn should pass the value on Business logic layer and then an appropriate message can be displayed on UI.

 

CREATE PROCEDURE  usp_yourprocedure
 -- Add the parameters for the stored procedure here
@Name varchar(15)
AS
BEGIN
DECLARE @Exist int
 -- SET NOCOUNT ON added to prevent extra result sets from
 -- interfering with SELECT statements.
 SET NOCOUNT ON;

    -- Insert statements for procedure here
 

IF EXISTS(SELECT * FROM Cities Where CityName = @Name)
BEGIN
SET @Exist = 1
END

END
SELECT @Exist
GO

END
GO

Hope this helps.
Good luck.

hi,

just use the following query

if not exists(select name from table1)
insert into table command



so if name would not exist then only it  will entry in table

Try this code, which will first check entered user name is exists or not... and if exists it will show message box else it will insert record;

SqlConnection con = new SqlConnection("YourConnectionString");

if (con != null)

{

  using (con)

  {

    if (con.State == System.Data.ConnectionState.Closed)

    {

      con.Open();

    }

    string query = "Select * from yourTable where UserName='" + textBox1.Text + "'";

    SqlDataAdapter da = new SqlDataAdapter(query, con);

    DataSet ds = new DataSet();

    da.Fill(ds);

    if (ds.Tables[0].Rows.Count > 0)

    {

      MessageBox.Show("User with this name is already exists!");

    }

    else

    {

      //You can insert record here....

    }

  }

}

-- Use Below Code :