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PHP面向?qū)ο蟮念I(lǐng)域模型+數(shù)據(jù)映射器實(shí)例介紹,很多新手對(duì)此不是很清楚,為了幫助大家解決這個(gè)難題,下面小編將為大家詳細(xì)講解,有這方面需求的人可以來(lái)學(xué)習(xí)下,希望你能有所收獲。
因原書(shū)中領(lǐng)域模型+數(shù)據(jù)映射器的示例代碼是連貫在一起的 所以這里就整理在一起了。
簡(jiǎn)單介紹一下我的看法,從數(shù)據(jù)庫(kù)操作的角度看領(lǐng)域模型主要是操作數(shù)據(jù)表中的單條記錄的而數(shù)據(jù)映射器是操作整個(gè)數(shù)據(jù)表的數(shù)據(jù)的。
按原文的解釋數(shù)據(jù)映射器是一個(gè)負(fù)責(zé)將數(shù)據(jù)庫(kù)數(shù)據(jù)映射到對(duì)象的類,而領(lǐng)域模型象征著真實(shí)世界里項(xiàng)目中的各個(gè)參與者,它在數(shù)據(jù)中通常表現(xiàn)為一條記錄。
廢話不多說(shuō),代碼和注解如下:
與領(lǐng)域模型相關(guān)的三個(gè)數(shù)據(jù)表結(jié)構(gòu)分別為venue(場(chǎng)所)、space(空間)、event(事件)。
create table 'venue' ( 'id' int(11) not null auto_increment, 'name' text, primary key ('id') ) create table 'space' ( 'id' int(11) not null auto_increment, 'venue' int(11) default null, 'name' text, primary key ('id') ) create table 'event' ( 'id' int(11) not null auto_increment, 'space' int(11) default null, 'start' mediumtext, 'duration' int(11) default null, 'name' text, primary key ('id') )
//領(lǐng)域模型(這里只建了一個(gè)Venue類用于理解) namespace woo\domain; abstract class DomainObject{ //抽象基類 private $id; function __construct ($id=null){ $this->id = $id; } function getId(){ return $this->id; } //原書(shū)沒(méi)有具體實(shí)現(xiàn),應(yīng)該是用于獲取對(duì)象的從屬對(duì)象的,比如venue(場(chǎng)所)相關(guān)的space(空間)對(duì)象 //具體的代碼實(shí)現(xiàn)中應(yīng)該從數(shù)據(jù)庫(kù)中查詢了相關(guān)數(shù)據(jù)并調(diào)用了Collection類,下面看到這個(gè)類的時(shí)候會(huì)有一個(gè)了解 //而且這個(gè)方法的實(shí)現(xiàn)應(yīng)該放在子類中才對(duì) static function getCollection($type){ return array(); } function collection(){ return self::getCollection(get_class($this)); } } class Venue extends DomainObject { private $name; private $spaces; function __construct ($id = null,$name=null){ $this->name= $name; $this->spaces = self::getCollection('\\woo\\domain\\space'); //這里應(yīng)該證明了我上述的猜測(cè) parent::__construct($id); } function setSpaces(SpaceCollection $spaces){ $this->spaces = $spaces; } function addSpace(Space $space){ $this->spaces->add($space); $space->setVenue($this); } function setName($name_s){ $this->name = $name_s; $this->markDirty(); } function getName(){ return $this->name; } } //數(shù)據(jù)映射器(正如原文的解釋數(shù)據(jù)映射器是一個(gè)負(fù)責(zé)將數(shù)據(jù)庫(kù)數(shù)據(jù)映射到對(duì)象的類) namespace woo\mapper; abstract class Mapper{ //抽象基類 abstract static $PDO; //操作數(shù)據(jù)庫(kù)的pdo對(duì)象 function __construct (){ if(!isset(self::$PDO){ $dsn = \woo\base\ApplicationRegistry::getDSN(); if(is_null($dsn)){ throw new \woo\base\AppException("no dns"); } self::$PDO = new \PDO($dsn); self::$PDO->setAttribute(\PDO::ATTR_ERRMODE,\PDO::ERRMODE_EXCEPTION); } } function createObject($array){ //將數(shù)組創(chuàng)建為上述領(lǐng)域模型中的對(duì)象 $obj = $this->doCreateObject($array); //在子類中實(shí)現(xiàn) return $obj; } function find($id){ //通過(guò)ID從數(shù)據(jù)庫(kù)中獲取一條數(shù)據(jù)并創(chuàng)建為對(duì)象 $this->selectStmt()->execute(array($id)); $array= $this->selectStmt()->fetch(); $this->selectStmt()->closeCursor(); if(!is_array($array)){ return null; } if(!isset($array['id'])){ return null; } $object = $this->createObject($array); return $object; } function insert(\woo\domain\DomainObject $obj){ //將對(duì)象數(shù)據(jù)插入數(shù)據(jù)庫(kù) $this->doInsert($obj); } //需要在子類中實(shí)現(xiàn)的各抽象方法 abstract function update(\woo\domain\DomainObject $objet); protected abstract function doCreateObject(array $array); protected abstract function selectStmt(); protected abstract function doInsert(\woo\domain\DomainObject $object); } //這里只建立一個(gè)VenueMapper類用于理解 class VenueMapper extends Mapper { function __construct (){ parent::__construct(); //各種sql語(yǔ)句對(duì)象 $this->selectStmt = self::$PDO->prepare("select * from venue where id=?"); $this->updateStmt = self::$PDO->prepare("update venue set name=?,id=? where id=?"); $this->insertStmt = self::$PDO->prepare("insert into venue (name) values(?)"); } protected function getCollection(array $raw){ //將Space數(shù)組轉(zhuǎn)換成對(duì)象 return new SpaceCollection($raw,$this); //這個(gè)類的基類在下面 } protected function doCreateObject (array $array){ //創(chuàng)建對(duì)象 $obj = new \woo\domain\Venue($array['id']); $obj->setname($array['name']); return $obj; } protected function doInsert(\woo\domain\DomainObject $object){ //將對(duì)象插入數(shù)據(jù)庫(kù) print 'inserting'; debug_print_backtrace(); $values = array($object->getName()); $this->insertStmt->execute($values); $id = self::$PDO->lastInsertId(); $object->setId($id); } function update(\woo\domain\DomainObject $object){ //修改數(shù)據(jù)庫(kù)數(shù)據(jù) print "updation\n"; $values = array($object->getName(),$object->getId(),$object->getId()); $this->updateStmt->execute($values); } function selectStmt(){ //返回一個(gè)sql語(yǔ)句對(duì)象 return $this->selectStmt; } }
Iterator接口定義的方法:
rewind() 指向列表開(kāi)頭
current() 返回當(dāng)前指針處的元素
key() 返回當(dāng)前的鍵(比如,指針的指)
next()
valid()
下面這個(gè)類是處理多行記錄的,傳遞數(shù)據(jù)庫(kù)中取出的原始數(shù)據(jù)和映射器進(jìn)去,然后通過(guò)數(shù)據(jù)映射器在獲取數(shù)據(jù)時(shí)將其創(chuàng)建成對(duì)象
abstract class Collection implements \Iterator{ protected $mapper; //數(shù)據(jù)映射器 protected $total = 0; //集合元素總數(shù)量 protected $raw = array(); //原始數(shù)據(jù) private $result; private $pointer = 0; //指針 private $objects = array(); //對(duì)象集合 function __construct (array $raw = null,Mapper $mapper= null){ if(!is_null($raw)&& !is_null($mapper)){ $this->raw = $raw; $this->total = count($raw); } $this->mapper = $mapper; } function add(\woo\domain\DmainObject $object){ //這里是直接添加對(duì)象 $class = $this->targetClass(); if(!($object instanceof $class)){ throw new Exception("This is a {$class} collection"); } $this->notifyAccess(); $this->objects[$this->total] = $object; $this->total ++; } abstract function targetClass(); //子類中實(shí)現(xiàn)用來(lái)在插入對(duì)象時(shí)檢查類型的 protected function notifyAccess(){ //不知道干嘛的 } private function getRow($num){ //獲取集合中的單條數(shù)據(jù),就是這里通過(guò)數(shù)據(jù)映射器將數(shù)據(jù)創(chuàng)建成對(duì)象 $this->notifyAccess(); if($num >= $this->total || $num < 0){ return null; } if(isset($this->objects[$num]){ return $this->objects[$num]; } if(isset($this->raw[$num]){ $this->objects[$num] = $this->mapper->createObject($this->raw[$num]); return $this->objects[$num]; } } public function rewind(){ //重置指針 $this->pointer = 0; } public function current(){ //獲取當(dāng)前指針對(duì)象 return $this->getRow($this->pointer); } public function key(){ //獲取當(dāng)前指針 return $this->pointer; } public function next(){ //獲取當(dāng)前指針對(duì)象,并將指針下移 $row = $this->getRow($this->pointer); if($row){$this->pointer ++} return $row; } public function valid(){ //驗(yàn)證 return (!is_null($this->current())); } } //子類 class VenueColletion extends Collection implements \woo\domain\VenueCollection{ function targetClass(){ return "\woo\domain\Venue"; } } //客戶端 $mapper = new \woo\mapper\VenueMapper(); $venue = $mapper->find(12); print_r($venue); $venue = new \woo\domain\Venue(); $venue->setName("the likey lounge-yy"); //插入對(duì)象到數(shù)據(jù)庫(kù) $mapper->insert($venue); //從數(shù)據(jù)庫(kù)中讀出剛才插入的對(duì)象 $venue = $mapper->find($venue->getId()); print_r($venue); //修改對(duì)象 $venue->setName("the bibble beer likey lounge-yy"); //調(diào)用update來(lái)更新記錄 $mapper->update($venue); //再次讀出對(duì)象數(shù)據(jù) $venue = $mapper->find($venue->getId()); print_r($venue); //結(jié)束
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