If it is very view specific, you can put them in a view helper.
If these methods are needed in almost all the controllers then you can put them in a superclass. Otherwise put them in a helper module and mix it in the controllers that requires it. Think about your application requirements and use your judgement. Instead of speculating, you could refactor it later.
I would also separate the business rule logic code from the data manipulation code. This will allow code reuse.