CakePHP的3通過相關數據

Question

在CakePHP 3刪除濾波，假設我想刪除所有部門有一些員工命名爲「約翰」（部門有多少員工，員工所屬部門）

最簡單的方法是過濾所有的部門，並在foreach循環刪除它們一個接一個：

$departments = $this->Departments->find() 
    ->matching('Employees', function ($q) { 
     return $q->where(['Employees.name' => 'John']); 
    }) 
    ->all(); 

foreach ($departments as $department) { 
    $this->Departments->delete($department); 
} 

這將導致一個SELECT查詢加上每條記錄DELETE查詢。我希望只有一個查詢被數據庫發送和執行。事情是這樣的：

DELETE Departments 
FROM departments Departments 
INNER JOIN employees Employees ON 
    Employees.department_id = Departments.id 
    AND Employees.name = 'John'; 

閱讀中，我發現三種方式來刪除記錄文檔：

• Using the Table object one by one，獲取對象，然後將其刪除。
• Using the Table with deleteAll，它在目標表上接受一系列條件，而不是相關聯的條件。
• Using the ORM，同樣只有一系列條件。

有沒有一種優雅的方式來使用CakePHP 3和ORM獲取我的查詢？

Answer 1

deleteAll只是圍繞

$this->Departments->query() 
    ->delete() 
    ->where([...]) 
    ->execute(); 

一個包裹所以我雖然是，以類似的方式，將有可能做到：

$departments = $this->Departments->query() 
    ->delete() 
    ->matching('Employees', function ($q) { 
     return $q->where(['Employees.name' => 'John']); 
    }) 
    ->execute(); 

但在這種情況下，你會發現，匹配條件被忽略。我看到有一個開放的ticket有關

如果你想只使用兩個查詢，你可以做一個查詢檢索所有的ID和刪除所有在第二個查詢：

$departments_ids = $this->Departments->find() 
    ->select(['id']) 
    ->matching('Employees', function ($q) { 
     return $q->where(['Employees.name' => 'John']); 
    }) 
    ->toArray(); 

$this->Departments->deleteAll(['id' => $departments_ids ]); 

導致在類似的東西：

DELETE FROM departments WHERE id IN 
(
    // id list here 
) 

另一種解決方案可以將您的內部聯接轉換爲子查詢。實際上你想要刪除幾乎有一個名爲John的員工的所有部門。

$employees = $this->Departments->Employees->find() 
    ->select(['department_id']) 
    ->distinct() 
    ->where(['Employees.name' => 'John']); 

$departments = $this->Departments->query() 
    ->delete() 
    ->where(['id IN' => $employees]) 
    ->execute(); 

Answer 2

兩件事情：

第一：我建議的方案是不正確

我的真實情況要複雜得多，所以我做了著名的員工部門爲例的情況。我犯了一個錯誤：我需要的是刪除屬於某個部門的所有員工。我想從相關表的基於表的條件中刪除數據。

事實上，你不能刪除有僱員姓名約翰的部門，因爲部門不是空的，還有約翰！ ：d

事情是這樣的：

-- Create structures 
CREATE TABLE IF NOT EXISTS departments (
    id int(11) NOT NULL AUTO_INCREMENT, 
    name varchar(45) NOT NULL, 
    PRIMARY KEY (id) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=4 ; 

CREATE TABLE IF NOT EXISTS employees (
    id int(11) NOT NULL AUTO_INCREMENT, 
    department_id int(11) NOT NULL, 
    name varchar(45) NOT NULL, 
    PRIMARY KEY (id), 
    KEY fk_employees_department_idx (department_id) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=5 ; 

ALTER TABLE employees 
    ADD CONSTRAINT fk_employees_departments FOREIGN KEY (department_id) REFERENCES departments (id) ON DELETE NO ACTION ON UPDATE NO ACTION; 


-- Populate some data 
INSERT INTO departments (id, name) VALUES 
(1, 'Sales'), 
(2, 'TI'), 
(3, 'HHRR'); 

INSERT INTO employees (id, department_id, name) VALUES 
(1, 1, 'John'), 
(2, 1, 'Mary'), 
(3, 2, 'Mark'), 
(4, 3, 'Lorenzo'); 


-- Delete all employees that belong to the TI department (Mark should be removed) 
DELETE emp FROM employees emp 
INNER JOIN departments dep ON emp.department_id = dep.id AND dep.name = 'TI'; 

第二：你可以在CakePHP中做到這一點很容易

你可以得到以前的查詢相同的結果這樣做：

$departments = $this->Employees->Departments->find() 
     ->select(['Departments.id']) 
     ->where(['Departments.name' => 'TI']); 
    $this->Employees->deleteAll(['Employees.department_id IN' => $departments]); 

由此產生的MySQL查詢將是：

DELETE FROM employees WHERE department_id in 
(SELECT Departments.id AS `Departments__id` 
FROM departments Departments 
WHERE Departments.name = 'TI') 

......這是正確的，而且容易理解。 @arilia，你用第一個答案指出了這個方向。對不起，我對此深表歉意。