<?php

        interface db{

              function conn();

          }

        interface Factory{

            function createDB();

        }

        class dbmysql implements db{

            public function conn(){

                echo "连上了mysql数据库";

            }

        }

        class dbsqlite implements db{

            public function conn(){

                echo "连上了dbsqlite数据库";

            }

        }

        class  mysqlFactory implements Factory{

               public function createDB(){

                return new dbmysql();

               }

        }

        class  sqliteFactory implements Factory{

              public function createDB(){

                return new dbsqlite();

              }

        }

        //添加数据库oracle

        class dboracle implements db{

            public function conn(){

                echo "连接上了oracle数据库";

            }

        }

        class oracleFactory implements Factory{

            public function createDB(){

                return new  dboracle();

            }

        }

        //客户端开始

        $fact=new mysqlFactory();

        $db=$fact->createDB();

        $db->conn();