Store text file into mysql Database in c#

Question

i read file through c# and the format of file is this.
INPUT FILE

00001740,      0.125,      0,      able
00001740,      0.125,      0,      unable
00002098,      0,          0.75,   country
00002312,      0,          0,      love    

i want this file in MYSQL Database. i write the code which store each line in each ROW of database. but the following code WRITE only the first line of the text file

 private void button1_Click(object sender, EventArgs e)
        {
            string MyConString = "server=localhost;" +
                "database=zahid;" + "password=zia;" +
                "User Id=root;";
            MySqlConnection connection = new MySqlConnection(MyConString);
            MySqlCommand command = connection.CreateCommand();
            MySqlDataReader Reader;
            connection.Open();
            StreamReader reader = new StreamReader("D:\\out.txt");

            string line;
            while ((line = reader.ReadLine()) != null)
            {   
                string[] parts = line.Split(',');
                command.CommandText = "insert into score(POS_ID,Pos,Neg,Word) values('" + parts[1] + "','" + parts[2] + "','" + parts[3] + "','" + parts[4] + "')";



                Reader = command.ExecuteReader();      
            }
        } 

this code return only the First line , but i want that all lines of text file store in the Database . thanks in advance

Answer 1

Try cleaning the mess:

private void button1_Click(object sender, EventArgs e)
{
    string[] lines = File.ReadAllLines("D:\\out.txt");
    foreach (var line in lines)
    {
        var data = line.Split(new[] { ',' }, 4);
        int posId = int.Parse(data[0].Trim());
        double pos = double.Parse(data[1].Trim());
        double neg = double.Parse(data[2].Trim());
        string word = data[3].Trim();
        StoreRecord(posId, pos, neg, word);
    }
}

private void StoreRecord(int posId, double pos, double neg, string word)
{
    var conStr = "server=localhost; database=zahid; password=zia; User Id=root;";
    using (var connection = new MySqlConnection(conStr)) 
    using (var command = connection.CreateCommand())
    {
        connection.Open();
        command.CommandText = 
        @"INSERT INTO score 
            (POS_ID, Pos, Neg, Word) 
          VALUES 
            (@posId, @pos, @neg, @word)";
        command.Parameters.AddWithValue("@posId", posId);
        command.Parameters.AddWithValue("@pos", pos);
        command.Parameters.AddWithValue("@neg", neg);
        command.Parameters.AddWithValue("@word", word);
        command.ExecuteNonQuery();
    }
}

Things to notice:

• separating the database insert logic into a dedicated method to avoid doing parsing and db inserts in the same place
• usage of using statemenets to properly dispose IDisposable resources such as connections and commands
• usage of parametrized queries to avoid SQL injection

Also you probably don't want to be rolling your own CSV parser using String.Split but use a real CSV parser instead.

If the CSV file is big you could read it one line at a time to avoid loading it in memory at once:

private void button1_Click(object sender, EventArgs e)
{
    using (var stream = File.OpenRead("D:\\out.txt"))
    using (var reader = new StreamReader(stream))
    {
        string line;
        while ((line = reader.ReadLine()) != null)
        {
            var data = line.Split(new[] { ',' }, 4);
            int posId = int.Parse(data[0].Trim());
            double pos = double.Parse(data[1].Trim());
            double neg = double.Parse(data[2].Trim());
            string word = data[3].Trim();
            StoreRecord(posId, pos, neg, word);
        }
    }
}