patbef-ServiceOutside/ServiceShared/Database/Migrations/Version_2.cs

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

namespace ServiceShared.Database.Migrations
{
    public class Version_2 : Migration
    {
        public Version_2()
        {
            this.Version = 2;
        }

        /**
         * Run current migration
         **/
        public override bool Run(DbContext dbContext)
        {
            bool result = false;

            try
            {
                if(this.RunPrevious(dbContext))
                {
                    if(!this.Ready(dbContext))
                    {
                        using (MySqlConnection client = dbContext.CreateConnection())
                        {
                            client.Open();
                           
                            MySqlCommand cmd = client.CreateCommand();
                            
                            /** add new column not_found_counter **/
                            cmd.CommandText = "alter table results add column not_found_counter int(11) not null default 0";
                            cmd.ExecuteNonQuery();

                            /** add new coulmn not_found_ts **/
                            cmd.CommandText = "alter table results add column not_found_ts datetime null";
                            cmd.ExecuteNonQuery();

                            /** add new column notification_counter **/
                            cmd.CommandText = "alter table results add column notification_counter int(11) not null default 0";
                            cmd.ExecuteNonQuery();

                            client.Close();
                            result = true;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                Log.Error(ex, "ServiceOutside.Database.Migrations.Version_2", "Run");
            }

            return result;
        }

        /// <summary>
        /// Checks if current migration already run
        /// </summary>
        /// <param name="dbContext">Database context for the migration</param>
        /// <returns></returns>
        private bool Ready(DbContext dbContext)
        {
            bool result = false;

            try
            {
                using (MySqlConnection client = dbContext.CreateConnection())
                {
                    client.Open();

                    MySqlCommand cmd = client.CreateCommand();
                    cmd.CommandText = "select not_found_counter, notification_counter from results where 1 <> 1";
                    cmd.ExecuteNonQuery();
                    client.Close();
                    result = true;
                }
            }
            catch
            {
                result = false;
            }

            return result;
        }

        /**
         * Runs/Checks previous migrations
         **/
        public override bool RunPrevious(DbContext dbContext)
        {
            bool result = false;

            try
            {
                if(new Version_1().Run(dbContext))
                {
                    result = true;
                }
            }
            catch (Exception ex)
            {
                Log.Error(ex, "ServiceOutside.Database.Migrations.Version_2", "RunPrevious");
            }

            return result;
        }
    }
}