[PHP] Two ideas for updating intermediate association table data, PHP ideas_PHP tutorial

<span>/*<br />|-----------------------------------------------------------<br />|方法一：先全部删除旧数据，后添加新数据<br />|@chenwei <www.chenwei.ws>
|-----------------------------------------------------------<br />*/
</span><span>$res</span> = <span>$this</span>->classes->classEdit(<span>$id</span>, <span>$data</span>);　　<span>//</span><span>修改主表数据</span>
                
<span>if</span>(<span>$res</span><span>)
{
　　</span><span>//</span><span>先删除关联表数据</span>
　　<span>$bool</span> = <span>$this</span>->lesson_classes->lessonClassesDel(<span>$id</span><span>);
                    
　　</span><span>if</span>(<span>$bool</span><span>)
　　{<br />　　　　//循环组装条件，添加数据
　　　　</span><span>foreach</span>(<span>$lesson_ids</span> <span>as</span> <span>$val</span><span>)<br />　　　　{
　　　　　　</span><span>$arr</span> = <span>array</span>('class_id'=><span>$id</span>, 'lesson_id'=><span>$val</span><span>);　　　　//数据<br />
　　　　　　</span><span>$res</span> = <span>$this</span>->lesson_classes->lessonClassesAdd(<span>$arr</span><span>);　 //执行添加
　　　　}
　　}
</span><span>               
　　</span><span>$this</span>->show_tips('操作成功！'<span>);
}
</span><span>else</span><span>
{
　　</span><span>$this</span>->show_tips('操作失败！'<span>);
}<br /><br />//弊端：大批量删除数据这块儿不安全，存在一定程度的安全隐患。<br /></span>

<span>/*<br />|---------------------------------------------------------<br />|方法二：只添加需要的，只删要删的<br />|@chenwei <www.chenwei.ws>
|---------------------------------------------------------<br />*/
//库中查出的旧数据：</span><span>$arr_old</span><span>　(处理过的一维数组)
//提交过来的新数据：</span><span>$arr_new</span><span>　(得到的一维数组)

</span><span>$intersect</span> = <span>array_intersect</span>(<span>$arr_old</span>, <span>$arr_new</span>);　　　<span>//</span><span>交集（需要保留的部分，不用处理）</span>

<span>$result_del</span> = <span>array_diff</span>(<span>$arr_old</span>, <span>$intersect</span>);　　　　<span>//</span><span>旧数据中需要删除的</span>

<span>$result_add</span> = <span>array_diff</span>(<span>$arr_new</span>, <span>$intersect</span>);　　　　<span>//</span><span>新数据中需要增加的

//添加新增数据</span>
<span>if</span>(<span>$result_add</span> && <span>is_array</span>(<span>$result_add</span><span>))
{
    </span><span>foreach</span>(<span>$result_add</span> <span>as</span> <span>$val</span><span>)
    {
        </span><span>$data_add</span> = <span>array</span>('class_id'=><span>$id</span>, 'lesson_id'=><span>$val</span><span>);　　　　　　　//数据
        
        $bool_add = </span><span>$this</span>->lesson_classes->lessonClassesAdd(<span>$data_add</span><span>);　　//执行添加
    }
}

</span><span>//</span><span>删除需要清除的数据</span>
<span>if</span>(<span>$result_del</span> && <span>is_array</span>(<span>$result_del</span><span>))
{
    </span><span>foreach</span>(<span>$result_del</span> <span>as</span> <span>$val</span><span>)
    {
        </span><span>$bool_del</span> = <span>$this</span>->lesson_classes->lessonClassesDel(<span>$id</span>, <span>$val</span><span>);  //执行删除
    }
}<br /><br />if($bool_add && $bool_del)<br />{<br />　　$this->show_tips('操作成功！');<br />}<br />else<br />{<br />　　$this->show_tips('操作失败！');<br />}<br /><br /><br />//特点：有针对性的添加数据和删除数据，较第一种方法，安全性高</span>