[coder_d]

Hello
I want to enter a value in a text box to add it in the database, but this value may be found already in the database
This code adds data from text box to the database, but without solving the problem of repetition of the same value that already exist in the database

   private void button1_Click(object sender, EventArgs e)
        {
            
                da.InsertCommand = new SqlCommand("INSERT INTO MyTable VALUES(@Username,@Password)", sc);
                da.InsertCommand.Parameters.Add("@Username", SqlDbType.VarChar).Value = textBox1.Text;
                da.InsertCommand.Parameters.Add("@Password", SqlDbType.VarChar).Value = textBox2.Text;
                sc.Open();
                da.InsertCommand.ExecuteNonQuery();
                sc.Close();
            
        }

Please help

[Joyal1234]

The below logic can work for you:
1. The database table column can be made primary key(if possible in your application)
2. If the entered value is repeated, SQL exception will be thrown that can be handled in the catch block where you can call the code of entering the value again.

Suggestions are invited on my solution.

This post has been edited by Joyal1234: 21 August 2011 - 11:10 PM

[andy_pleasants]

Alternatively you can just enforce a unique key constraint on that column. It doesn't have to be your primary key then, but will need to be unique