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HomeDatabaseMysql TutorialYii 操作数据库_MySQL

参考:

query方式:https://github.com/yii2-chinesization/yii2-zh-cn/blob/master/guide-zh-CN/db-query-builder.md

Active Record模式 :https://github.com/yii2-chinesization/yii2-zh-cn/blob/master/guide-zh-CN/db-active-record.md


建立数据库链接

class Customer extends ActiveRecord{    // ...    public static function getDb()    {        return /Yii::$app->db2;  // 使用名为 "db2" 的应用组件  默认是db    }}

声明AR类

namespace app/models;use yii/db/ActiveRecord;class Customer extends ActiveRecord{    /**     * @return string 返回该AR类关联的数据表名     */    public static function tableName()    {        return 'customer';    }}

查询数据

// 取回所有活跃客户(状态为 *active* 的客户)并以他们的 ID 排序:$customers = Customer::find()    ->where(['status' => Customer::STATUS_ACTIVE]) //Customer中定义的常量    ->orderBy('id')    ->all();// 返回ID为1的客户:$customer = Customer::find()    ->where(['id' => 1])    ->one();// 取回活跃客户的数量:$count = Customer::find()    ->where(['status' => Customer::STATUS_ACTIVE])    ->count();// 以客户ID索引结果集:$customers = Customer::find()->indexBy('id')->all();// $customers 数组以 ID 为索引// 用原生 SQL 语句检索客户:$sql = 'SELECT * FROM customer';$customers = Customer::findBySql($sql)->all();

有两个快捷方法:findOne 和 findAll() 用来返回一个或者一组ActiveRecord实例。前者返回第一个匹配到的实例,后者返回所有。 例如:

// 返回 id 为 1 的客户$customer = Customer::findOne(1);// 返回 id 为 1 且状态为 *active* 的客户$customer = Customer::findOne([    'id' => 1,    'status' => Customer::STATUS_ACTIVE,]);// 返回id为1、2、3的一组客户$customers = Customer::findAll([1, 2, 3]);// 返回所有状态为 "deleted" 的客户$customer = Customer::findAll([    'status' => Customer::STATUS_DELETED,]);
数组形式获取数据
// 以数组而不是对象形式取回客户信息:$customers = Customer::find()    ->asArray()    ->all();// $customers 的每个元素都是键值对数组
批量获取数据
// 一次提取 10 个客户信息foreach (Customer::find()->batch(10) as $customers) {    // $customers 是 10 个或更少的客户对象的数组}// 一次提取 10 个客户并一个一个地遍历处理foreach (Customer::find()->each(10) as $customer) {    // $customer 是一个 ”Customer“ 对象}// 贪婪加载模式的批处理查询foreach (Customer::find()->with('orders')->each() as $customer) {}
例子:
// 插入新客户的记录$customer = new Customer();$customer->name = 'James';$customer->email = 'james@example.com';$customer->save();  // 等同于 $customer->insert();// 更新现有客户记录$customer = Customer::findOne($id);$customer->email = 'james@example.com';$customer->save();  // 等同于 $customer->update();// 删除已有客户记录$customer = Customer::findOne($id);$customer->delete();// 删除多个年龄大于20,性别为男(Male)的客户记录Customer::deleteAll('age > :age AND gender = :gender', [':age' => 20, ':gender' => 'M']);// 所有客户的age(年龄)字段加1:Customer::updateAllCounters(['age' => 1]);

查询关联数据

class Customer extends /yii/db/ActiveRecord{    public function getOrders()    {        // 客户和订单通过 Order.customer_id -> id 关联建立一对多关系        return $this->hasMany(Order::className(), ['customer_id' => 'id']);    }}class Order extends /yii/db/ActiveRecord{    // 订单和客户通过 Customer.id -> customer_id 关联建立一对一关系    public function getCustomer()    {        return $this->hasOne(Customer::className(), ['id' => 'customer_id']);    }}
join类型关联查询
// 查找所有订单并以客户 ID 和订单 ID 排序,并贪婪加载 "customer" 表$orders = Order::find()->joinWith('customer')->orderBy('customer.id, order.id')->all();// 查找包括书籍的所有订单,并以 `INNER JOIN` 的连接方式即时加载 "books" 表$orders = Order::find()->innerJoinWith('books')->all();





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