CakePHP的3通过相关数据

Question

在CakePHP 3删除滤波，假设我想删除所有部门有一些员工命名为“约翰”（部门有多少员工，员工所属部门）

最简单的方法是过滤所有的部门，并在foreach循环删除它们一个接一个：

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

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

这将导致一个SELECT查询加上每条记录DELETE查询。我希望只有一个查询被数据库发送和执行。事情是这样的：

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

阅读中，我发现三种方式来删除记录文档：

• Using the Table object one by one，获取对象，然后将其删除。
• Using the Table with deleteAll，它在目标表上接受一系列条件，而不是相关联的条件。
• Using the ORM，同样只有一系列条件。

有没有一种优雅的方式来使用CakePHP 3和ORM获取我的查询？

Answer 1

deleteAll只是围绕

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

一个包裹所以我虽然是，以类似的方式，将有可能做到：

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

但在这种情况下，你会发现，匹配条件被忽略。我看到有一个开放的ticket有关

如果你想只使用两个查询，你可以做一个查询检索所有的ID和删除所有在第二个查询：

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

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

导致在类似的东西：

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

另一种解决方案可以将您的内部联接转换为子查询。实际上你想要删除几乎有一个名为John的员工的所有部门。

$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

两件事情：

第一：我建议的方案是不正确

我的真实情况要复杂得多，所以我做了著名的员工部门为例的情况。我犯了一个错误：我需要的是删除属于某个部门的所有员工。我想从相关表的基于表的条件中删除数据。

事实上，你不能删除有雇员姓名约翰的部门，因为部门不是空的，还有约翰！ ：d

事情是这样的：

-- 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中做到这一点很容易

你可以得到以前的查询相同的结果这样做：

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

由此产生的MySQL查询将是：

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

......这是正确的，而且容易理解。 @arilia，你用第一个答案指出了这个方向。对不起，我对此深表歉意。