HOW TO READ AND COMPARE DATA FROM AN SQL SERVER EXPRESS DATABASE

john rob

Total Post:108

Points:756
Posted by  john rob
C# 
C#
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I am trying to create a select statement in C# to check if the value inserted into a textbox (userName) is in an existing SQL database. I have a database called Employee containing a table called EVUSERS and it has a column called UName.

In my code I have a method which takes the value from a textbox called UserBox. I would like to know if there is a temporary table where the select is stored which I can compare the textbox value to.

Here is the code:

private void CheckLoginExist()

{

            String userName = UserBox.Text;

            string connectionString = @"Data Source=.\SQLEXPRESS;Database=Employee;Integrated Security=true";

            using (SqlConnection connection = new SqlConnection(connectionString))

            {

                using (SqlCommand command = connection.CreateCommand())

                {

                    command.CommandText = "SELECT UName FROM EVUSERS WHERE UName = @UName";

                    command.Parameters.AddWithValue("@UName", userName);

                    connection.Open();

                    command.ExecuteNonQuery();

                    connection.Close();

                }

            }

}

  1. Pravesh Singh

    Post:412

    Points:2888
    Re: How to read and compare data from an SQL Server Express database

    Hi John,


    You need ExecuteScalar, not ExecuteNonQuery

    connection.Open();

    var name = command.ExecuteScaclar().ToString();

    connection.Close();

    if (name != null) {

      MessageBox.Show("This name already exists");

      return;

    }

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