using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Text;

namespace DAL
{
    public class DA
    {
        private static SqlConnection m_con;
        private static SqlCommand m_cmd;
        private static SqlDataReader m_dre;
        private static SqlDataAdapter m_dap;
        private static DA m_instance;
        
        public static DA GetInstance() 
        {
            if (m_instance != null)
            {
                return m_instance;
            }
            else
            {
                return new DA();
            }
        }

        private DA() 
        {
            m_con = new SqlConnection("Data Source=(local)\\SQLEXPRESS;Initial Catalog=FHRep;Integrated Security=SSPI");
            m_cmd = new SqlCommand();
            m_cmd.Connection = m_con;
        }

        public int ExecuteQuery(string sqlQuery) 
        {
            m_cmd.CommandType = CommandType.Text;
            m_cmd.CommandText = sqlQuery;
            m_con.Open();
            int count = m_cmd.ExecuteNonQuery();
            m_con.Close();
            return count;
        }

        public DataSet Query(string sqlQuery) 
        {
            m_dap = new SqlDataAdapter(sqlQuery, m_con);
            DataSet ds = new DataSet();
            m_dap.Fill(ds);
            return ds;
        }

        public SqlDataReader DataReader(string sqlQuery) 
        {
            m_cmd.CommandType = CommandType.Text;
            m_cmd.CommandText = sqlQuery;
            m_con.Open();
            m_dre = m_cmd.ExecuteReader();
            m_con.Close();
            return m_dre;
        }
    }
}