[rcleveng]

If your language supports generators, this works a lot better than making copies of the entire dataset too.

[akshayshah]

Sometimes, sure - but sometimes, passing around a fat wrapper around a DB cursor is worse, and the code would be better off paginating and materializing each page of data in memory. As usual, it depends.

[KlayLay]

You don't need your programming language to implement generators for you. You can implement them yourself.