SOLID principle - Single responsability - Bad example

badExample.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Threading.Tasks;
using MySql.Data.MySqlClient;

namespace MyDataManipulationApp{

	public class DataManipulation{

		private string serverIp;
		private string databaseName;
		private string userName;
		private string userPassword;
		private MySqlConnection connection;
		private MySqlCommand query;
		private MySqlDataReader dataReader;
		private string fileName;

		// Use the constructor to connect to the database
		public void DataManipulation(){
			this.connect();
		}
		
		private void connect(){
			this.connection = new MySqlConnection(
	                "server=" + this.serverIp + ";" +
	                "userid=" + this.userName + ";" +
	                "password=" + this.userPassword + ";" +
	                "database=" + this.databaseName + ";" 
	            );
			this.connection.open();
			this.command = this.connection;
			
		}
		private void disconnect(){
			this.connection.close();
		}

		private List<string> ReadInformation(){
			this.command = "SELECT id,name,stock,description from products WHERE active;";
			this.dataReader = this.command.ExecuteReader();
			List<string> list = (
				from IDataRecord r in this.dataReader
				select (string)r["FieldName"]
			    ).ToList();
			return list;
		}

		public void WriteFile(){
			this.fileName = @"C:\temp\activeProducts.txt";

			foreach(string row in this.ReadInformation){
				File.WriteAllText(
					fileName,
					row["id"].toString() +
					row["name"].toString() +
					row["stock"].toString() +
					row["description"].toString() +
					Environment.NewLine
				);		
			}
			this.disconnect();			
		}
	}
}