Validation rule for a composite unique index (non-primary)

I am sure I am not the first who has composite unique keys in tables and who wants to validate them. I do not want to invent the bicycle so I ask here first. I have several table开发者_C百科s that have 'id' columns as primary keys and two other columns as unique composite keys. It would be nice to have a validation rule to check that the submitted entry is unique and display a validation error if it is not. In Cakephp it could be done by a custom validation rule. I am pretty sure somebody has created such method already.

Ideally it would be a method in app_model.php that could be used by different models.

I am using that function:

function checkUnique($data, $fields) {
    if (!is_array($fields)) {
            $fields = array($fields);
        }
        foreach($fields as $key) {
            $tmp[$key] = $this->data[$this->name][$key];
        }
    if (isset($this->data[$this->name][$this->primaryKey]) && $this->data[$this->name][$this->primaryKey] > 0) {
            $tmp[$this->primaryKey." !="] = $this->data[$this->name][$this->primaryKey];
        }
    //return false;
        return $this->isUnique($tmp, false); 
    }

basically the usage is:

'field1' => array(
                'checkUnique' => array(
                    'rule' => array('checkUnique', array('field1', 'field2')),
                    'message' => 'This field need to be non-empty and the row need to be unique'
                ),
            ),
'field2' => array(
                'checkUnique' => array(
                    'rule' => array('checkUnique', array('field1', 'field2')),
                    'message' => 'This field need to be non-empty and the row need to be unique'
                ),
            ),

So basically this will show the warning under each of the fields saying that it's not unique.

I am using this a lot and it's working properly.

In the CakePHP/2.x versions released in the last few years, the isUnique rule optionally accepts several columns:

You can validate that a set of fields are unique by providing multiple fields and set $or to false:

public $validate = array(
    'email' => array(
        'rule' => array('isUnique', array('email', 'username'), false),
        'message' => 'This username & email combination has already been used.'
    )
);

I'm not sure of the exact version when the feature was available but there's a bug fixed in core as late as October 2014 filed against 2.3 and 2.4 branches.

You could put it in app model, but my suggestion would just be to add it to the model directly by placing the rule with it's $validate property.

Check out the built in isUnique rule.