cakePHP验证existsIn（）for empty / Null字段，如何摆脱......？

Question

I have 2 tables Orders and Products. In orders table has foreign key product_id. Sometimes it's not necessary that order must contain the product(order without any product id is allowed). In this scenario my existIn validation rule causing the problem to save data.

$rules->add($rules->existsIn(['product_id'], 'Products'));  //Validation in the model of Orders.

N.B. - Keep in mind that I have allowed product_id to be null in my DB.

Answer 1

Edit: Per the comment by ndm existsIn checking for null or existing in should be the default functionality of existsIn if your column is nullable in the database. If its not working perhaps you are passing some kind of value accidentally or your column is not listed as nullable.

You should also be able to override the exists in to allow for this or other conditions. Basically you will specify an exists in or it is a certain value. In this case null.

Answer modified from How to build rule exist in or equal to a number in cakephp 3?

$rules->add(
function ($entity, $options) {
    $rule = new ExistsIn(['product_id'], 'Products');
    return $entity->product_id === NULL || $rule($entity, $options);
},
    ['errorField' => 'product_id', 'message' => 'Product ID specified but does not exist']
);