Foreign key validation rule in Yii2

Question

I have parent_id that can have NULL value - default sets to 0.

Model

...
[['parent_id'], 'integer'],
[['parent_id'], 'default', 'value' => 0],
[['parent_id'], 'exist', 'targetAttribute' => 'id', 'skipOnEmpty' => true],
...

But exist rule didn't work.

What I'm doing wrong?

UPDATE

Today I removed the following rule and it works:

...
[['parent_id'], 'default', 'value' => 0],
...

But what do I do if want to change the default to other value?

Answer 1

change the order of rules:

[['parent_id'], 'integer'],
[['parent_id'], 'exist', 'targetAttribute' => 'id', 'skipOnEmpty' => true],
[['parent_id'], 'default', 'value' => 0],