1 多表聯查實現方法
有兩種方式一種使用DAO寫SQL語句實現，這種實現理解起來相對輕鬆，只要保證SQL語句不寫錯就行了。缺點也很明顯，比較零散，而且不符合YII的推薦框架，最重要的缺點在於容易寫錯。
還有一種便是下面要說的使用YII自帶的CActiveRecord實現多表聯查
2 整體框架
我們需要找到一個用戶的好友關係，用戶的信息放在用戶表中，用戶之間的關係放在關係表中，而關係的內容則放在關係類型表中。明顯的我們只需要以關係表爲主表聯查其他兩個表即可。我主要從代碼的角度，分析下實現的過程。
3 CActiveRecord
我們首先需要對3張表建立相應的model，下面是關係表的代碼
SocialRelation.php
<?php
/**
* This is the model class for table "{{social_relation}}".
*
* The followings are the available columns in table '{{social_relation}}':
* @property integer $relation_id
* @property integer $relation_type_id
* @property integer $user_id
* @property integer $another_user_id
*
* The followings are the available model relations:
* @property SocialRelationType $relationType
* @property AccessUser $user
* @property AccessUser $anotherUser
*/
class SocialRelation extends CActiveRecord
{
/**
* Returns the static model of the specified AR class.
* @param string $className active record class name.
* @return SocialRelation the static model class
*/
public static function model($className=__CLASS__)
{
return parent::model($className);
}
/**
* @return string the associated database table name
*/
public function tableName()
{
return '{{social_relation}}';
}
/**
* @return array validation rules for model attributes.
*/
public function rules()
{
// NOTE: you should only define rules for those attributes that
// will receive user inputs.
return array(
array('relation_type_id, user_id, another_user_id', 'numerical', 'integerOnly'=>true),
// The following rule is used by search().
// Please remove those attributes that should not be searched.
array('relation_id, relation_type_id, user_id, another_user_id', 'safe', 'on'=>'search'),
);
}
/**
* @return array relational rules.
*/
public function relations()
{
// NOTE: you may need to adjust the relation name and the related
// class name for the relations automatically generated below.
return array(
'relationType' => array(self::BELONGS_TO, 'SocialRelationType', 'relation_type_id'),
'user' => array(self::BELONGS_TO, 'AccessUser', 'user_id'),
'anotherUser' => array(self::BELONGS_TO, 'AccessUser', 'another_user_id'),
);
}
/**
* @return array customized attribute labels (name=>label)
*/
public function attributeLabels()
{
return array(
'relation_id' => 'Relation',
'relation_type_id' => 'Relation Type',
'relation_type_name' => 'Relation Name',
'user_id' => 'User ID',
'user_name' => 'User Name',
'another_user_id' => 'Another User',
'another_user_name' => 'Another User Name',
);
}
/**
* Retrieves a list of models based on the current search/filter conditions.
* @return CActiveDataProvider the data provider that can return the models based on the search/filter conditions.
*/
public function search()
{
// Warning: Please modify the following code to remove attributes that
// should not be searched.
$criteria=new CDbCriteria;
$criteria->compare('relation_id',$this->relation_id);
$criteria->compare('relation_type_id',$this->relation_type_id);
$criteria->compare('user_id',$this->user_id);
$criteria->compare('another_user_id',$this->another_user_id);
$criteria->with=array(
'relationType',
);
return new CActiveDataProvider($this, array(
'criteria'=>$criteria,
));
}
}爲了描述方便我們約定 主表爲A表(執行查詢的那個表)， 引用表爲B表(外鍵所引用的表)
1 model函數、tablename函數用於得到這個模型和得到數據庫表基本信息。自動生成無需修改
2 rules函數，這個函數主要用於規定參數檢驗方式，注意即使有些參數不需要校驗，也必須出現在rules中。不然模型將無法得到參數
3 relation函數，這個函數十分關鍵，用於定義表之間的關係，下面我將詳細說明其中含義
'relationType' => array(self::BELONGS_TO, 'SocialRelationType', 'relation_type_id')'VarName'=>array('RelationType', 'ClassName', 'ForeignKey', ...additional options)
VarName 是關係的名字，我們以後會用這個名字訪問外鍵引用表的字段
RelationType是關係的類型，十分重要，如果設定錯誤會導致一些奇怪而且難以檢查的錯誤，Yii一共提供了4種關係
BELONGS_TO（屬於）: 如果表 A 和 B 之間的關係是一對多，則 表 B 屬於 表 A
HAS_MANY（有多個）: 如果表 A 和 B 之間的關係是一對多，則 A 有多個 B
HAS_ONE（有一個）: 這是 HAS_MANY 的一個特例，A 最多有一個 B
MANY_MANY: 這個對應於數據庫中的 多對多關係
ClassName是引用表名，就是外鍵所引用的表的名字，也就是B表表名
ForeignKey是外鍵名，主要這裏填寫的是外鍵在主表中的名字，也就是外鍵在A表中的表名，切記不要填錯了
如果B表中是雙主鍵可以採用下列方式實現，從軟件工程的角度不推薦這樣的做法，每個表最好使用獨立無意義主鍵，不然容易出現各種問題，而且不方便管理
'categories'=>array(self::MANY_MANY, 'Category',
'tbl_post_category(post_id, category_id)'),4 attributeLabels函數，這就是表屬性的顯示名稱了，有點點像powerdesigner中code和name的關係前面一部分爲數據庫字段名，後面一部分爲顯示名稱
5 search函數，用於生成表查詢結果的函數，可以在此加一些限制條件，具體的使用方法就不在這裏說明了，可以參考API中CDbCriteria的講解。如果使用Gii生成那麼不需要怎麼修改。
同理我們生成，剩下的兩個引用表
關係類型表：SocialRelationType.php
<?php
/**
* This is the model class for table "{{social_relation_type}}".
*
* The followings are the available columns in table '{{social_relation_type}}':
* @property integer $relation_type_id
* @property string $relation_type_name
*
* The followings are the available model relations:
* @property SocialRelation[] $socialRelations
*/
class SocialRelationType extends CActiveRecord
{
/**
* Returns the static model of the specified AR class.
* @param string $className active record class name.
* @return SocialRelationType the static model class
*/
public static function model($className=__CLASS__)
{
return parent::model($className);
}
/**
* @return string the associated database table name
*/
public function tableName()
{
return '{{social_relation_type}}';
}
/**
* @return array validation rules for model attributes.
*/
public function rules()
{
// NOTE: you should only define rules for those attributes that
// will receive user inputs.
return array(
array('relation_type_name', 'length', 'max'=>10),
// The following rule is used by search().
// Please remove those attributes that should not be searched.
array('relation_type_id, relation_type_name', 'safe', 'on'=>'search'),
);
}
/**
* @return array relational rules.
*/
public function relations()
{
// NOTE: you may need to adjust the relation name and the related
// class name for the relations automatically generated below.
return array(
'socialRelations' => array(self::HAS_MANY, 'SocialRelation', 'relation_type_id'),
);
}
/**
* @return array customized attribute labels (name=>label)
*/
public function attributeLabels()
{
return array(
'relation_type_id' => 'Relation Type',
'relation_type_name' => 'Relation Type Name',
);
}
/**
* Retrieves a list of models based on the current search/filter conditions.
* @return CActiveDataProvider the data provider that can return the models based on the search/filter conditions.
*/
public function search()
{
// Warning: Please modify the following code to remove attributes that
// should not be searched.
$criteria=new CDbCriteria;
$criteria->compare('relation_type_id',$this->relation_type_id);
$criteria->compare('relation_type_name',$this->relation_type_name,true);
return new CActiveDataProvider($this, array(
'criteria'=>$criteria,
));
}
}用戶表：AccessUser.php
<?php
/**
* This is the model class for table "{{access_user}}".
*
* The followings are the available columns in table '{{access_user}}':
* @property integer $id
* @property string $name
* @property string $password
* @property string $lastlogin
* @property string $salt
* @property string $email
* @property integer $status
*
* The followings are the available model relations:
* @property SocialRelation[] $socialRelations
* @property SocialRelation[] $socialRelations1
*/
class AccessUser extends CActiveRecord
{
/**
* Returns the static model of the specified AR class.
* @param string $className active record class name.
* @return AccessUser the static model class
*/
public static function model($className=__CLASS__)
{
return parent::model($className);
}
/**
* @return string the associated database table name
*/
public function tableName()
{
return '{{access_user}}';
}
/**
* @return array validation rules for model attributes.
*/
public function rules()
{
// NOTE: you should only define rules for those attributes that
// will receive user inputs.
return array(
array('status', 'numerical', 'integerOnly'=>true),
array('name, password, salt, email', 'length', 'max'=>255),
array('lastlogin', 'safe'),
// The following rule is used by search().
// Please remove those attributes that should not be searched.
array('id, name, password, lastlogin, salt, email, status', 'safe', 'on'=>'search'),
);
}
/**
* @return array relational rules.
*/
public function relations()
{
// NOTE: you may need to adjust the relation name and the related
// class name for the relations automatically generated below.
return array(
'user_name' => array(self::HAS_MANY, 'SocialRelation', 'user_id'),
'anotherUser_name' => array(self::HAS_MANY, 'SocialRelation', 'another_user_id'),
);
}
/**
* @return array customized attribute labels (name=>label)
*/
public function attributeLabels()
{
return array(
'id' => 'ID',
'name' => 'Name',
'password' => 'Password',
'lastlogin' => 'Lastlogin',
'salt' => 'Salt',
'email' => 'Email',
'status' => 'Status',
);
}
/**
* Retrieves a list of models based on the current search/filter conditions.
* @return CActiveDataProvider the data provider that can return the models based on the search/filter conditions.
*/
public function search()
{
// Warning: Please modify the following code to remove attributes that
// should not be searched.
$criteria=new CDbCriteria;
$criteria->compare('id',$this->id);
$criteria->compare('name',$this->name,true);
$criteria->compare('password',$this->password,true);
$criteria->compare('lastlogin',$this->lastlogin,true);
$criteria->compare('salt',$this->salt,true);
$criteria->compare('email',$this->email,true);
$criteria->compare('status',$this->status);
return new CActiveDataProvider($this, array(
'criteria'=>$criteria,
));
}
}三張表介紹完了後，下面就應當介紹Controller了，同樣的我們使用Gii生成主表（A表）的CRUD後就能得到controller，我們只需要對其進行一些修改即可，代碼如下
SocialRelationController.php
<?php
class SocialRelationController extends Controller
{
/**
* @var string the default layout for the views. Defaults to '//layouts/column2', meaning
* using two-column layout. See 'protected/views/layouts/column2.php'.
*/
public $layout='//layouts/column2';
/**
* @return array action filters
*/
public function filters()
{
return array(
'accessControl', // perform access control for CRUD operations
'postOnly + delete', // we only allow deletion via POST request
);
}
/**
* Specifies the access control rules.
* This method is used by the 'accessControl' filter.
* @return array access control rules
*/
public function accessRules()
{
return array(
array('allow', // allow all users to perform 'index' and 'view' actions
'actions'=>array('index','view'),
'users'=>array('*'),
),
array('allow', // allow authenticated user to perform 'create' and 'update' actions
'actions'=>array('create','update'),
'users'=>array('@'),
),
array('allow', // allow admin user to perform 'admin' and 'delete' actions
'actions'=>array('admin','delete'),
'users'=>array('admin'),
),
array('deny', // deny all users
'users'=>array('*'),
),
);
}
/**
* Displays a particular model.
* @param integer $id the ID of the model to be displayed
*/
public function actionView($id)
{
$this->render('view',array(
'model'=>$this->loadModel($id),
));
}
/**
* Creates a new model.
* If creation is successful, the browser will be redirected to the 'view' page.
*/
public function actionCreate()
{
$model=new SocialRelation;
// Uncomment the following line if AJAX validation is needed
// $this->performAjaxValidation($model);
if(isset($_POST['SocialRelation']))
{
$model->attributes=$_POST['SocialRelation'];
if($model->save())
$this->redirect(array('view','id'=>$model->relation_id));
}
$this->render('create',array(
'model'=>$model,
));
}
/**
* Updates a particular model.
* If update is successful, the browser will be redirected to the 'view' page.
* @param integer $id the ID of the model to be updated
*/
public function actionUpdate($id)
{
$model=$this->loadModel($id);
// Uncomment the following line if AJAX validation is needed
// $this->performAjaxValidation($model);
if(isset($_POST['SocialRelation']))
{
$model->attributes=$_POST['SocialRelation'];
if($model->save())
$this->redirect(array('view','id'=>$model->relation_id));
}
$this->render('update',array(
'model'=>$model,
));
}
/**
* Deletes a particular model.
* If deletion is successful, the browser will be redirected to the 'admin' page.
* @param integer $id the ID of the model to be deleted
*/
public function actionDelete($id)
{
$this->loadModel($id)->delete();
// if AJAX request (triggered by deletion via admin grid view), we should not redirect the browser
if(!isset($_GET['ajax']))
$this->redirect(isset($_POST['returnUrl']) ? $_POST['returnUrl'] : array('admin'));
}
/**
* Lists all models.
*/
public function actionIndex()
{
if(Yii::app()->user->id != null){
$dataProvider=new CActiveDataProvider(
'SocialRelation',
array('criteria'=>array('condition'=>'user_id='.Yii::app()->user->id,
))
);
$this->render('index',array(
'dataProvider'=>$dataProvider,
));
}
}
/**
* Manages all models.
*/
public function actionAdmin()
{
$model=new SocialRelation('search');
$model->unsetAttributes(); // clear any default values
if(isset($_GET['SocialRelation']))
$model->attributes=$_GET['SocialRelation'];
$this->render('admin',array(
'model'=>$model,
));
}
/**
* Returns the data model based on the primary key given in the GET variable.
* If the data model is not found, an HTTP exception will be raised.
* @param integer $id the ID of the model to be loaded
* @return SocialRelation the loaded model
* @throws CHttpException
*/
public function loadModel($id)
{
$model=SocialRelation::model()->findByPk($id);
if($model===null)
throw new CHttpException(404,'The requested page does not exist.');
return $model;
}
/**
* Performs the AJAX validation.
* @param SocialRelation $model the model to be validated
*/
protected function performAjaxValidation($model)
{
if(isset($_POST['ajax']) && $_POST['ajax']==='social-relation-form')
{
echo CActiveForm::validate($model);
Yii::app()->end();
}
}
}
$layout 就是佈局文件的位置了，佈局文件如何使用，這裏不做討論
filters 定義過濾器，這裏面水很深
accessRules 訪問方式，就是那些用戶能夠訪問到這個模塊
array('allow', // allow all users to perform 'index' and 'view' actions
'actions'=>array('index','view'),
'users'=>array('*'),
),action，表示規定規則使用的動作
user，表示規則適用的用戶羣組，*表示所有用戶,@表示登錄後的用戶,admin表示管理員用戶
actionXXX 各個action函數
這裏值得注意的是 這個函數
public function actionIndex()
{
if(Yii::app()->user->id != null){
$dataProvider=new CActiveDataProvider(
'SocialRelation',
array('criteria'=>array('condition'=>'user_id='.Yii::app()->user->id,
))
);
$this->render('index',array(
'dataProvider'=>$dataProvider,
));
}
}loadModel 用於裝載模型，這裏我們可以看到findByPk查詢了數據庫，具體使用方式常見API 和 手冊
performAjaxValidation 用於Ajax驗證
5 視圖View
index.php
<?php
/* @var $this SocialRelationController */
/* @var $dataProvider CActiveDataProvider */
$this->breadcrumbs=array(
'Social Relations',
);
?>
<h1>Social Relations</h1>
<?php $this->widget('zii.widgets.CListView', array(
'dataProvider'=>$dataProvider,
'itemView'=>'_view',
)); ?>
我們使用一個 CListView控件進行顯示，其中itemView爲內容顯示的具體表單，dataProvider這個是內容源，我們在controller中已經設定了。
_view.php<?php
/* @var $this SocialRelationController */
/* @var $data SocialRelation */
?>
<div class="view">
<b><?php echo CHtml::encode($data->getAttributeLabel('relation_id')); ?>:</b>
<?php echo CHtml::link(CHtml::encode($data->relation_id), array('view', 'id'=>$data->relation_id)); ?>
<br />
<b><?php echo CHtml::encode($data->getAttributeLabel('relation_type_id')); ?>:</b>
<?php echo CHtml::encode($data->relation_type_id); ?>
<br />
<b><?php echo CHtml::encode($data->getAttributeLabel('relation_type_name')); ?>:</b>
<?php
echo $data->relationType->relation_type_name;
?>
<br />
<b><?php echo CHtml::encode($data->getAttributeLabel('user_id')); ?>:</b>
<?php echo CHtml::encode($data->user_id); ?>
<br />
<b><?php echo CHtml::encode($data->getAttributeLabel('user_name')); ?>:</b>
<?php
echo $data->user->name;
?>
<br />
<b><?php echo CHtml::encode($data->getAttributeLabel('another_user_id')); ?>:</b>
<?php echo CHtml::encode($data->another_user_id); ?>
<br />
<b><?php echo CHtml::encode($data->getAttributeLabel('another_user_name')); ?>:</b>
<?php
echo $data->anotherUser->name;
?>
<br />
</div> <b><?php echo CHtml::encode($data->getAttributeLabel('relation_type_name')); ?>:</b>
<?php echo $data->relationType->relation_type_name; ?>第二行爲內容顯示，這裏的relationType是在模型中設置的關係名字，後面的relation_type_name是引用表的字段名(B表中的名字)
6 總結
通過上面的步驟，我們就實現了整個聯合查詢功能，效果圖如下所示。
7 參考網站
YII手冊： http://www.yiiframework.com/doc/guide/1.1/zh_cn/database.ar