# Attach, detach and sync many-to-many relationships in Laravel

## 1.attach is insert value to pivot table relation

when we run this code `$user->roles()->attach([3]);` that will be add/insert data to table user_role

| role_id| user_id |
| ------ | -----   |
| 3      | 1       |

## 2.sync is add value and delete to pivot table relation

If user_role table have

| role_id| user_id |
| ------ | -----   |
| 1      | 1       |
| 2      | 1       |

```php

// run this syntax
$user->roles()->sync([3, 2])

```

| role_id| user_id |
| ------ | -----   |
| 2      | 1       |
| 3      | 1       |


## 3. detach is remove value in pivot table relation

If we have data like this

| role_id| user_id |
| ------ | -----   |
| 2      | 1       |
| 3      | 1       |
| 1      | 1       |

when we try to run this code `$user->roles()->detach();` that will be remove all data, but if we add the arguments on function detach `$user->roles()->detach(1);` will remove only `role_id : 1`

| role_id| user_id |
| ------ | -----   |
|    |        |


## 4. syncWithoutDetaching is add value without detach and duplicate when run twice

Let say we have table with value like this

| role_id| user_id |
| ------ | -----   |
| 3      | 1       |

when we insert using code `syncWithoutDetaching` example `$user->roles()->syncWithoutDetaching([1, 2]);` will be insert value role_id `1 and 2`

| role_id| user_id |
| ------ | -----   |
| 3      | 1       |
| 1      | 1       |
| 2      | 1       |