Laravel 8 validate unique through columns and rows on create and update

Question

I have got 3 columns in my table email_1, email_2, email_3. How to avoid duplicates between the rows while create and update?

For the update method, I can validate by columns like this:

public function rules()
{
    /** OTHER VALIDATION RULES */

    'email_1' => [
    'required',
    'email',
    'unique:users,email_1,' . $this->id,
    ],
    'email_2' => [
    'required',
    'email',
    'unique:users,email_2,' . $this->id,
    ],
    'email_3' => [
    'required',
    'email',
    'unique:users,email_3,' . $this->id,
    ]
    /** OTHER VALIDATION RULES */
}

The problem is avoiding using the same email address on the three input fields of my form?

Answer 1

Method 1

The easiest way is to use the different validation rule. Something like this:

'email_1' => [
  'required',
  'email',
  'different:email_2'
  'different:email_3',
  'unique:users,email,' . $this->id,
],
'email_2' => [
  'required',
  'email',
  'different:email_1'
  'different:email_3',
  'unique:users,email_2,' . $this->id,
],
'email_3' => [
  'required',
  'email',
  'different:email_1'
  'different:email_2',
  'unique:users,email_3,' . $this->id,
],

Method 2

I see you're validating within a Request class, which is great because you can make use of After Hooks.

public function withValidator($validator)
{
    $emails = [Request['email_1'], Request['email_2'], Request['email_3']];
    $validator->after(function ($validator) use ($emails) {
        if (count($emails) == count(array_unique($emails))) {
            // Add error to message bag.
            $validator->errors()->add('key', 'message');
        }
    });
}

The above example uses array_unique(), which will remove duplicates. Comparing length of original vs length of deduplicated one will show if duplicates are present.