Is there an official Magento 1.x Module Development Reference/Documentation?

Hi people, I had been selected recently to manage and improve an ecommerce with Magento 1.9 and they asked me to build several custom attribute modules so I figured how to build the basics about, but in the install of the module, I need to know the constants that I can use in “used_in_forms” because …

Is there an official Magento 1.x Module Development Reference/Documentation? Read More »