Mysql Query in c#

Question

I'm going to write a program that finds the score of paragraph. The database file has a score of words.
database file

    Word                       Pos_Score            

    intelligent               .987              
    allows                    .378               
    agree                     .546              
    industries                .289               
    guests                    .874

Using SELECT query and WHERE class i compared paragraph words with database file.
paragraph:

I agree with you.  It seems an intelligent tourist industry allows its guests to either immerse fully, in part, or not, depending upon the guest.

the above paragraph have some words that matched the database file word so the score of that word will be extracted.
Program output should be like this

Pos_score= .987+.378+.546+.289+.874=3.074

Code

private void button1_Click(object sender, EventArgs e)
        {
            string MyConString = "server=localhost;" +"database=sentiwornet;" + "password=zia;" +"User Id=root;";
            StreamReader reader = new StreamReader("D:\\input.txt");
            float amd=0;
            string line;
            float pos1 = 0;
            while ((line = reader.ReadLine()) != null)
            {
                string[] parts = line.Split(' ');
                MySqlConnection connection = new MySqlConnection(MyConString);
                MySqlCommand command = connection.CreateCommand();
                MySqlDataReader Reader;

                foreach (string part in parts)
                {

                    command.CommandText = "SELECT Pos_Score FROM score WHERE Word = part";
                    try
                    {
                        amd = (float)command.ExecuteScalar();
                        pos1 = amd + pos1;
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.Message);
                    }
                    Reader = command.ExecuteReader();
                    connection.Open();
                }
            }
            MessageBox.Show("The Positive score of Sentence is="+pos1.ToString());
            reader.Close();
        }

but this code is not working and it gives the following error.

Error 1
Object reference not set to an instance of an object

Error 2
Connection must be valid and open.

first check that you are getting connection string value or not from MyConString and second error occur's because one of your function is close your connection.so plz check ExecuteScalar() and ExecuteReader() function carefully.. — Rahul
– Rahul, Commented Mar 20, 2013 at 8:40
@Prasad: if i open connection first then this problem occur:**Unknown column 'part' in 'where clause'** — Zia Ur Rehman
– Zia Ur Rehman, Commented Mar 20, 2013 at 8:42

Prasad · Accepted Answer · 2013-03-20 08:57:25Z

i think this must be 1st problem...

private void button1_Click(object sender, EventArgs e)
    {
        string MyConString = "server=localhost;" +"database=sentiwornet;" + "password=zia;" +"User Id=root;";
        StreamReader reader = new StreamReader("D:\\input.txt");
        float amd=0;
        string line;
    MySqlConnection connection = new MySqlConnection(MyConString);
    connection.Open();
        MySqlCommand command = connection.CreateCommand();
        MySqlDataReader Reader;
        float pos1 = 0;
        while ((line = reader.ReadLine()) != null)
        {
            string[] parts = line.Split(' ');


            foreach (string part in parts)
            {

                command.CommandText = "SELECT Pos_Score FROM score WHERE Word = @part";
                command.Parameters.Add("@part",MySqlDBtype.Varchar).Value = part;
                try
                {
                    amd = (float)command.ExecuteScalar();
                    pos1 = amd + pos1;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
                Reader = command.ExecuteReader();

            }
        }
        MessageBox.Show("The Positive score of Sentence is="+pos1.ToString());
        reader.Close();
        connection.Close();
    }

Ikong · Accepted Answer · 2013-03-21 06:51:54Z

0

command.CommandText = "SELECT Pos_Score FROM score WHERE Word = " + part;

answered Mar 21, 2013 at 6:51

Ikong

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