Fixes #4607: AR model will throw an exception if it does not have a primary key…

framework/CHANGELOG.md

@@ -178,6 +178,7 @@ Yii Framework 2 Change Log
 - Enh #4581: Added ability to disable url encoding in `UrlRule` (tadaszelvys)
 - Enh #4597: `yii\composer\Installer::setPermission()` supports setting permission for both directories and files now (qiangxue)
 - Enh #4602: Added $key param in ActionColumn buttons Closure call (disem)
+- Enh #4607: AR model will throw an exception if it does not have a primary key to avoid updating/deleting data massively (qiangxue)
 - Enh #4630: Added automatic generating of unique slug value to `yii\behaviors\Sluggable` (klimov-paul)
 - Enh #4644: Added `\yii\db\Schema::createColumnSchema()` to be able to customize column schema used (mcd-php)
 - Enh #4656: HtmlPurifier helper config can now be a closure to change the purifier config object after it was created (Alex-Code)

framework/db/BaseActiveRecord.php

@@ -1008,10 +1008,14 @@ abstract class BaseActiveRecord extends Model implements ActiveRecordInterface
      * @return mixed the old primary key value. An array (column name => column value) is returned if the primary key
      * is composite or `$asArray` is true. A string is returned otherwise (null will be returned if
      * the key value is null).
+     * @throws Exception if the AR model does not have a primary key
      */
     public function getOldPrimaryKey($asArray = false)
     {
         $keys = $this->primaryKey();
+        if (empty($keys)) {
+            throw new Exception(get_class($this) . ' does not have a primary key. You should either define a primary key for the corresponding table or override the primaryKey() method.');
+        }
         if (count($keys) === 1 && !$asArray) {
             return isset($this->_oldAttributes[$keys[0]]) ? $this->_oldAttributes[$keys[0]] : null;
         } else {