Fix validation for ORM updating

Author: yidas

README.md

@@ -115,9 +115,11 @@ if ($post) {
 }
 ```
 
+> The pattern is similar to [Yii2 Active Record](https://www.yiiframework.com/doc/guide/2.0/en/db-active-record#active-record) and [Laravel Eloquent](https://laravel.com/docs/5.8/eloquent#inserting-and-updating-models)
+
 ### Find with Query Builder
 
-The Model would defined database coonnections and table itself.
+Start to use CodeIgniter Query Builder from `find()` method, the Model will automatically load its own database connections and data tables.
 
 ```php
 $records = $this->Posts_model->find()

src/Model.php

@@ -8,7 +8,7 @@
  * Base Model
  *
  * @author   Nick Tsai <myintaer@gmail.com>
- * @version  2.16.0
+ * @version  2.16.1
  * @see      https://github.com/yidas/codeigniter-model
  */
 class Model extends \CI_Model implements \ArrayAccess
@@ -338,6 +338,20 @@ public function validate($attributes=[], $returnData=false)
         // Get validation rules from function setting
         $rules = $this->rules();
 
+        // The ORM update will only collect rules with corresponding modified attributes.
+        if ($this->_selfCondition) {
+
+            $newRules = [];
+            foreach ((array) $rules as $key => $rule) {
+                if (isset($this->_writeProperties[$rule['field']])) {
+                    // Add into new rules for updating
+                    $newRules[] = $rule;
+                }
+            }
+            // Replace with mapping rules
+            $rules = $newRules;
+        }
+
         // CodeIgniter form_validation doesn't work with empty array data
         if (empty($rules) || empty($data))
             return ($returnData) ? $data : true;