Question

I’ve been trying to use the same SqlConnection and SqlCommand objects to execute to different commands.

the first one checks for duplicate and the second one inserts the data if the data the user entered is not a duplicate.

Here’s a sample of my code:

        using (SqlConnection conn = new SqlConnection(ConnStr))
        {
            string Command = "SELECT CountryName FROM [Countries] WHERE CountryName = @Name";

            using (SqlCommand comm = new SqlCommand(Command, conn))
            {
                comm.Parameters.Add("@Name", System.Data.SqlDbType.NVarChar, 20);
                comm.Parameters["@Name"].Value = Name;

                comm.Parameters.Add("@IsVisible", System.Data.SqlDbType.Bit);
                comm.Parameters["@IsVisible"].Value = IsVisible;

                conn.Open();

                if (comm.ExecuteScalar() == null)
                {
                        Command = "INSERT INTO [Countries] (CountryName, IsVisible) VALUES (@Name, @IsVisible);";
                        comm.ExecuteNonQuery();
                }
        }

I was trying to save a trip to the database by using one connection.

The Problem is:

The first command runs okay but the
second command which inserts into the
database won’t work (it doesn’t add
any records to the db) and when I
tried to display the rows affected it
gave me -1 !!

The Question is:

Is this is the ideal way to check for
a duplicate records to constraint a
unique country ? and why the second
command is not executing ?

Answer 1

When you rewrite the Command variable with the insert statement, you are simply modifying the string named Command that you’ve defined earlier. You are not modifying the command text stored inside of the SqlCommand object.

Try:

comm.CommandText = “INSERT INTO [Countries] (CountryName, IsVisible) VALUES (@Name, @IsVisible);”;