通用数据访问

/* 在开发过程中数据库可能用的很多，可能即用sqlserver 又用 oracle  等等........，总结了几次在网上看了很多资料写了个觉得还可以用的,需要修改的地方很多希望各位大哥指教，小弟在这里先谢了  */


namespace Connection
{
    class Program
    {
        static private string connString, sql;
        static IDbConnection conn = null;
        static IDbDataAdapter adapter = null;

        static void Main(string[] args)
        {

            int dbconn = Convert.ToInt32(Console.ReadLine());
            GenericAdoNetComp genDP = new GenericAdoNetComp();
            sql = "select * from spt_values";


            switch (dbconn)
            {
                case 1:
                    connString =
             "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=c:\\Northwind.mdb";
                    /* 取得数据库连接对象 ACCESS数据库代码连接    */
                    conn = genDP.GetConnection(ConnEnum.DbTypeConn.Oledb, connString);
                    adapter = genDP.GetDataAdapter(ConnEnum.DbTypeConn.Oledb, connString, sql);
                    break;


                case 2:

                    /*sqlserver 数据库练级*/
                    connString =
                    "Data Source=.;Initial Catalog=master;user id=sa;password=sa;";
                    conn = genDP.GetConnection(ConnEnum.DbTypeConn.Sql, connString);


                    adapter = genDP.GetDataAdapter(ConnEnum.DbTypeConn.Sql, connString, sql);
                    break;

                case 3:
                    conn = genDP.GetConnection(ConnEnum.DbTypeConn.Odbc, connString);
                    adapter = genDP.GetDataAdapter(ConnEnum.DbTypeConn.Odbc, connString, sql);
                    break;


            }

            try
            {
                conn.Open();
                DataSet ds = new DataSet();
                adapter.Fill(ds);



                if (ds.Tables.Count > 0)
                {

                    for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
                    {

                        for (int j = 0; j < ds.Tables[0].Columns.Count; j++)
                        {
                            Console.Write(ds.Tables[0].Rows[i][j]);
                        }



                    }
                }
            }
            catch (Exception exp)
            {
                throw exp;
            }
            finally
            {
                conn.Close();



            }



        }
    }
}



/*枚举 */



namespace ConnEnum
{

    public enum DbTypeConn
    {
        Oledb,
        Sql,
        Odbc,
    } 

}


/*接口，在这里简单的写了下三层模式没有写工厂模式，请见谅 */

namespace Connection
{
    interface  IConnection
    {
         IDbConnection GetConnection(DbTypeConn  connType, string connString);
         IDbDataAdapter GetDataAdapter(DbTypeConn connType, string connString, string sql);

    }
}


/* BLL */

namespace myenm
{


    public class GenericAdoNetComp : Connection.IConnection
    {
       
        
        private IDbConnection idbConn = null;
        private IDbDataAdapter idbAdapter = null;
   

 
        public GenericAdoNetComp()
        {
        }

        /* GetConnection returns IDbConnection   */
        public IDbConnection GetConnection(DbTypeConn ConnDbType, string connString)
        {
            switch (ConnDbType)
            {
                case ConnEnum.DbTypeConn.Oledb: // OleDb Data Provider
                    idbConn = new OleDbConnection(connString);
                    break;
                case ConnEnum.DbTypeConn.Sql: // Sql Data Provider
                    idbConn = new SqlConnection(connString);
                    break;
                case ConnEnum.DbTypeConn.Odbc: // ODBC Data Provider
                    idbConn = new OdbcConnection(connString);
                    break;
                // case 3: // Add your custom data provider
                default:
                    break;
            }
            return idbConn;

        }



        /* GetDataAdapter returns IDbDataAdapter  使用适配器模式读取数据  */
        public IDbDataAdapter GetDataAdapter(DbTypeConn ConnDbType,
        string connString, string sql)
        {
            switch (ConnDbType)
            {
                case ConnEnum.DbTypeConn.Oledb: // OleDb Data Provider
                    idbAdapter = new OleDbDataAdapter(sql, connString);
                    break;
                case  ConnEnum.DbTypeConn.Sql: // Sql Data Provider
                    idbAdapter = new SqlDataAdapter(sql, connString);
                    break;
                case ConnEnum.DbTypeConn.Odbc: // ODBC Data Provider
                    idbAdapter = new OdbcDataAdapter(sql, connString);
                    break;
                               // case 3: // Add your custom data provider
                default:
                    break;
            }
            return idbAdapter;
        }

    }
}