php - How to override classes in lib/Varien directory? -

i want override \lib\varien\data\collection\db.php. know how override creating same file path in local code pool. want know possible override class same way overriding models, blocks inside our modules? appreciated.

no, can not rewrite varien_data_collection_db dynamic way models, etc.

the reason simple: appropriate magento models use varien_data_collection_db base class , literally extend it:

abstract class mage_core_model_resource_db_collection_abstract extends varien_data_collection_db {} abstract class mage_eav_model_entity_collection_abstract extends varien_data_collection_db {} class mage_sales_model_resource_sale_collection extends varien_data_collection_db {} 

copying class local or community code pool way go.