Database.cs

using Discord;
using MySql.Data.MySqlClient;
using System;
using System.Collections.Generic;
using System.Linq;

namespace DeniedBot.MySQL
{
    public class Database
    {
        private string table { get; set; }
        private const string server = "localhost";
        private const string database = "denieddb";
        private const string username = "root";
        private const string password = "";
        private MySqlConnection connect;

        public Database(string table)
        {
            this.table = table;
            MySqlConnectionStringBuilder build = new MySqlConnectionStringBuilder();
            build.Server = server;
            build.Port = 3306;
            build.Database = database;
            build.UserID = username;
            build.Password = password;

            connect = new MySqlConnection(build.ToString());
            connect.Open();
        }

        public MySqlDataReader SendCommand(string query)
        {
            if (connect == null)
            {
                return null;
            }

            MySqlCommand cmd = new MySqlCommand(query, connect);
            return cmd.ExecuteReader();
        }

        public void close()
        {
            if (connect != null)
            {
                connect.Close();
            }
        }

        public static List<String> CheckExistingGuild(IGuild guild)
        {
            var result = new List<String>();
            var db = new Database("denieddb");

            var cmd = $"SELECT * FROM `guilds` WHERE id = `{guild.Id}`";
            var guilds = db.SendCommand(cmd);

            while (guilds.Read())
            {
                var g = (string)guilds["id"];
                result.Add(g);
            }

            return result;
        }

        public static void EnterGuild(IGuild guild)
        {
            var db = new Database("denieddb");

            var cmd = $"INSERT INTO `guilds` (id, name, joinleave, modlog) VALUES (`{guild.Id}`, `{guild.Name}`, `null`, `null`";
            db.SendCommand(cmd);
            db.close();
        }

        public static void DeleteGuild(IGuild guild)
        {
            var db = new Database("denieddb");

            var cmd = $"DELETE FROM `guilds` WHERE id = `{guild.Id}`";
            db.SendCommand(cmd);
            db.close();
        }

        public static List<Guilds> GetGuildStatus(IGuild guild)
        {
            var result = new List<Guilds>();
            var db = new Database("denieddb");

            var cmd = $"SELECT * FROM `guilds` WHERE id = `{guild.Id}`";
            var guilds = db.SendCommand(cmd);

            while (guilds.Read())
            {
                var id = (string)guilds["id"];
                var name = (string)guilds["name"];
                var joinleave = (ulong)guilds["joinleave"];
                var modlog = (ulong)guilds["modlog"];

                result.Add(new Guilds
                {
                    id = id,
                    name = name,
                    joinleave = joinleave,
                    modlog = modlog
                });
            }
            db.close();
            return result;
        }
    }
}