Yii2. How to validate the properties of different models depending on each other?

Question

Yii

How to validate the properties of different models depending on each other?
For example, the end date of model 2 must be greater than the start date of model 1.

Answer 1

Write your own validation rule. and then use in similar code.
if ($model1->validate()) {
$model2->temp_end = $model1->end_date;
if ($model2->validate()) {
// your code
}
}

Answer 2

write your own validator. in rules for the date of the second model

public function rules()
    {
        return [
            ....
            [['dateEnd'], 'dateValidate'],
        ];
    }

then the validator itself

public function dateValidate($attribute, $params)
{
        $model=Model_1::findOne(id);
        if($this->dateEnd<=$model->dateStart){
                $this->addError('dateEnd', 'Ошибка');
        }
}