I am working on a custom Joomla MVC component.
My view has a form where the user enters an ID. I have retrieved the ID ($input_id) in the controller. Now I need to query the database to get the name WHERE ID = $input_id, then write the name to a different database table.
Can this all be done within the controller or do I have to pass my variables to the model somehow? Not sure of the correct way to achieve this within the MVC framework.
All data and data manipulation should be done in the model (e.g. model your data). The controller is there to determine the path of execution and which methods should be called (e.g. the manager aka controller determines what needs to be done).
Have a look at this tutorial which will help you understand MVC for Joomla better by taking you through the development of a simple component.