大哥们，谁给看看这段代码的意思啊

 public class DAL_Select_Mobilenews
    {
        private static Database _db = null;
        protected static Database db
        {
            get
            {
                if (_db == null)
                    _db = DatabaseFactory.CreateDatabase("Selectmaishouji");
                return _db;
            }
        }          public static Model_Mobilenews GetMobilenewsByMobleID(int mobleid)
        {
            Model_Mobilenews info = null;
            string strSql = "select * from Mobilenews  where mobleid=@mobleid";
            DbCommand dbCommandWrapper = db.GetSqlStringCommand(strSql);
            db.AddInParameter(dbCommandWrapper, "@mobleid", DbType.Int32, mobleid);
            IDataReader dr = db.ExecuteReader(dbCommandWrapper);
            if (dr.Read())
                info = MobilenewsFormIDataReader(dr);
            dr.Close();
            return info;
        }
      }   这段代码，在DAL层的每个.cs文件里面几乎都有，看着像创建数据库的，可又云里雾里的 ，还有下面的                 db.GetSqlStringCommand(strSql);
 求解