mysql codeigniter活动记录m：m删除

问题描述：

我有一个表有两个有am：m关系的表，我可以想要的是，当我从一个表中删除一行时，我想让连接表中的行成为删除以及，我的SQL是如下，mysql codeigniter活动记录m：m删除

表1

CREATE TABLE IF NOT EXISTS `job_feed` (
    `id` int(11) NOT NULL AUTO_INCREMENT, 
    `body` text NOT NULL, 
    `date_posted` int(10) NOT NULL, 
    PRIMARY KEY (`id`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;

表2

CREATE TABLE IF NOT EXISTS `job_feed_has_employer_details` (
    `job_feed_id` int(11) NOT NULL, 
    `employer_details_id` int(11) NOT NULL, 
    PRIMARY KEY (`job_feed_id`,`employer_details_id`), 
    KEY `fk_job_feed_has_employer_details_job_feed1` (`job_feed_id`), 
    KEY `fk_job_feed_has_employer_details_employer_details1` (`employer_details_id`) 
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

所以我想要做的是，如果从table1中删除了一行，并且ID为1，那么我希望表中的那一行也具有该想法作为关系的一部分。

我想这样做与codeigniters活动记录类我目前有此一致，

public function deleteJobFeed($feed_id) 
    { 
     $this->db->where('id', $feed_id) 
       ->delete('job_feed'); 

     return $feed_id; 
    }

答

尝试是这样的（也许是我错了得到一些名字）：

public function deleteJobFeed($feed_id) 
{ 
    //Delete Job Feed 
    $this->db->where('id', $feed_id) 
     ->delete('job_feed'); 

    //Get Related Employer information ID from related table 
    $query = $this>db->where('job_feed_id', $feed_id) 
    ->get('job_feed_has_employer_details'); 
     if ($query->num_rows() > 0) 
     { 
      $row = $query->row(); 
      $employer_details_id = $row->employer_details_id; 
     } 
    //Now you have the employer details id. 
    //You can now delete the row you just got, and then use the id to find the row in the employer details table and delete that. 
    $this>db->where('job_feed_id', $feed_id) 
    ->delete('job_feed_has_employer_details'); 

    //I'm assuming your third table is called "employer details". You said you had a many to many relationship. 
    $this>db->where('employer_details_id', $employer_details_id) 
    ->delete('employer_details'); 

    return $feed_id; 
}

此外，如果你还没有看过它，我推荐http://www.overzealous.com/dmz/

它使处理关系的方式很容易。希望这可以帮助。

mysql codeigniter活动记录m：m删除

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