CakePHP 3 Validate unique within two columns

Question

I have a table of product sizes

Product Details
id  product_id size
1       1        m
1       1        l
2       2        l

If i try to add another detail to product 1 with size m it should return false but for product 2 size m should go through

In my Product Detail Table here is validator its something here

 //Product Detail Table
public function validationDefault(Validator $validator){
$validator
        ->add('size', 'unique', ['rule' => 'validateUnique', 'provider' => 'table'])

Not sure how to add a condition for column

Answer 1

That's what the scope option is there for, it allows you to add additional fields to the uniqueness constraint.

Unique validation can be scoped to the value of another column:

$validator->add('email', [
    'unique' => [
        'rule' => ['validateUnique', ['scope' => 'site_id']],
        'provider' => 'table'
    ]
]);

In the above example, the email uniqueness will be scoped to only rows having the same site_id. Scoping will only be used if the scoping field is present in the data to be validated.

API > \Cake\ORM\Table::validateUnique()

However, this should at least additionally be an application rule, as it's prone to race conditions, and thus needs to be checked in a transaction, which by default only happens for application rules.

You can use the built-in IsUnique rule, which you can simply pass multiple column names to.

use Cake\ORM\RulesChecker;

// ...

public function buildRules(RulesChecker $rules)
{
    $rules->add($rules->isUnique(['product_id', 'size']));

    return $rules;
}

See also

• Cookbook > Database Access & ORM > Validating Data > Applying Application Rules
• Cookbook > Database Access & ORM > Validating Data > Creating Unique Field Rules
• Cookbook > Database Access & ORM > Validating Data > Using Validation as Application Rules