// get the primary key of a record with ID 1 $record = MyModel::findOne(1); $primaryKey = $record->getPrimaryKey(); // output the primary key value(s) foreach ($primaryKey as $value) { echo $value; }This method is useful when you need to access the primary key value(s) of a record, for example, for use in generating URLs or for saving related records. The Yii framework is the package library used for this code example. It is a PHP web application framework that provides a solid foundation for developing web applications quickly and easily. It includes features like efficient database access through its `ActiveRecord` ORM, powerful caching mechanisms, and robust security features.