c# - SQL (MySQL, MSSQL, MS Access) kodbank

using System.Data.Sql;
using System.Data.SqlClient;
using System.Data.Odbc;

 public DataTable dt = new DataTable();

//MS Access bağlantı metni ---------------------------------

//string conn_str = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" +
//    Path.Combine(HostingEnvironment.ApplicationPhysicalPath, @"veritabani.mdb");

//-----------------------------------------------------

//MS SQL bağlantı metni

//public string conn_str = "Server=BS_ismi\\SQLEXPRESS;Database=isim;Trusted_Connection=True";
//public string conn_str = "Server=11.11.11.11;Initial Catalog=vt_isim; User Id=isim;Password=sifre";

//-----------------------------------------------------

//MySQL bağlantı metni

//public string conn_str = "Driver={MySQL ODBC 5.1 Driver};Server=11.11.11.11;Database=vt_isim;User=user;Password=sifre;Option=3";
// public string conn_str = "Driver={MySQL ODBC 5.1 Driver};Server=127.0.0.1;Database=vt_isim; User=username;Option=3";
   
    public OdbcCommand command = new OdbcCommand(); //MS Access veya MySQL için
    public OdbcConnection conn = new OdbcConnection();      //MS Access veya MySQL için
    //public SqlConnection conn = new SqlConnection();      //MSSQL için
    //public SqlCommand command = new SqlCommand();  //MSSQL için

// SELECT TABLO & SÜTUN İFADELERİ (SEÇME OKUMA)

 public DataTable sel(string DB, string columns, string opt)
    {
        string komut_s = "Select " + columns + " from " + DB + " " + opt;
        DataTable dat = new DataTable();
        try
        {
            conn.ConnectionString = conn_str;
            conn.Open();
            //SqlDataAdapter adapter = new SqlDataAdapter(komut_s, conn);
            OdbcDataAdapter adapter = new OdbcDataAdapter(komut_s, conn);
            adapter.Fill(dat);
            conn.Close();
            //lbl_error.Text = "";
        }
        catch (Exception ex)
        {
            //lbl_error.Text = ex.ToString();
        }
        finally
        {
            conn.Close();
        }
        return dat;
    }

// INSERT İFADESİ  (YENİ VERİ)

public bool ins(string DB, string props, string vals)
    {
        bool result = false;
        string komut_s = "Insert into " + DB + " (" + props + ") values (" + vals + ")";
        try
        {
            conn.ConnectionString = conn_str;
            conn.Open();
            command = conn.CreateCommand();
            command.CommandText = komut_s;
            command.ExecuteNonQuery();
            conn.Close();
            result = true;
            //lbl_error.Text = "";
        }
        catch (Exception ex)
        {
            //lbl_error.Text = ex.ToString();
        }
        finally
        {
            conn.Close();
        }
        return result;
    }

// UPDATE İFADESİ  (GÜNCELLEME)

    public bool upd(string DB, string vals, string condition)
    {
        bool result = false;
        string komut_s = "Update " + DB + " set " + vals + " where " + condition;
        try
        {
            conn.ConnectionString = conn_str;
            conn.Open();
            command = conn.CreateCommand();
            command.CommandText = komut_s;
            command.ExecuteNonQuery();
            conn.Close();
            result = true;
            //lbl_error.Text = "";
        }
        catch (Exception ex)
        {
            //lbl_error.Text = ex.ToString();
        }
        finally
        {
            conn.Close();
        }
        return result;
    }

//DELETE TABLODAN SIRA SİLME İFADESİ

    public bool del(string DB, string condition)
    {
        bool result = false;
        string komut_s = "Delete from " + DB + " where " + condition;
        try
        {
            conn.ConnectionString = conn_str;
            conn.Open();
            command = conn.CreateCommand();
            command.CommandText = komut_s;
            command.ExecuteNonQuery();
            conn.Close();
            //lbl_error.Text = "";
            result = true;
        }
        catch (Exception ex)
        {
            //lbl_error.Text = ex.ToString();
        }
        finally
        {
            conn.Close();
        }
        return result;
    }

// İSTENEN BİR KOMUTU UYGULAMA

    public string command_exec(string komut)
    {
        string result = "false";
        string komut_s = komut;
        try
        {
            conn.ConnectionString = conn_str;
            conn.Open();
            command = conn.CreateCommand();
            command.CommandText = komut_s;
            command.ExecuteNonQuery();
            conn.Close();
            //lbl_error.Text = "";
            result = "true";
        }
        catch (Exception ex)
        {
            result = ex.ToString();
            //lbl_error.Text = ex.ToString();
        }
        finally
        {
            conn.Close();
        }
        return result;
    }

//SELECT SCHEMA TABLOLAR İLE İLGİLİ BİLGİ OKUMA vb.

    public DataTable sel2(string komut)
    {
        string komut_s = komut;
        DataTable dat = new DataTable();
        try
        {
            conn.ConnectionString = conn_str;
            conn.Open();
            //SqlDataAdapter adapter = new SqlDataAdapter(komut_s, conn);
            OdbcDataAdapter adapter = new OdbcDataAdapter(komut_s, conn);
            adapter.Fill(dat);
            conn.Close();
            //lbl_error.Text = "";
        }
        catch (Exception ex)
        {
            //lbl_error.Text = ex.ToString();
        }
        finally
        {
            conn.Close();
        }
        return dat;
    }