問題描述

Laravel 4 的 Eloquent ORM 中的 attach() 和 sync() 有什么區(qū)別?我試圖環(huán)顧四周，但找不到任何東西！

attach():

• 在處理多對多關(guān)系時(shí)插入相關(guān)模型
• 不需要數(shù)組參數(shù)

示例:

$user = User::find(1);$user->roles()->attach(1);

sync():

與attach()方法類似，sync()方法用于附加相關(guān)模型.但是，主要區(qū)別在于:

• sync() 接受要放在數(shù)據(jù)透視表上的 ID 數(shù)組
• 其次，最重要的，如果數(shù)組中不存在模型，同步方法會從數(shù)據(jù)透視表中刪除數(shù)據(jù)，并只將新項(xiàng)目插入數(shù)據(jù)透視表.

示例:

user_role

$user = User::find(12);$user->roles()->sync(array(1, 2, 3));

以上操作將刪除:

然后將 role_id 3 插入到表中.

user_role 表

What is the difference between attach() and sync() in Laravel 4's Eloquent ORM? I've tried to look around but couldn't find anything!

attach():

• Insert related models when working with many-to-many relations
• No array parameter is expected

Example:

$user = User::find(1);
$user->roles()->attach(1);

sync():

Similar to the attach() method, the sync() method is used to attach related models. However, the main differences are:

• sync() accepts an array of IDs to place on the pivot table
• Secondly, most important, the sync method will delete the data from the pivot table if the model does not exist in the array, and insert only the new items to the pivot table.

Example:

user_role

id  user_id role_id
1    12       1
2    12       5
3    12       2

$user = User::find(12);
$user->roles()->sync(array(1, 2, 3));

The above operation will delete:

id  user_id role_id
2    12       5

And insert role_id 3 to the table.

user_role table

id  user_id role_id
1    12       1
3    12       2
4    12       3

這篇關(guān)于Laravel Eloquent - 附加與同步的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！