1. A method for operating a multi-level resistive random access memory (RRAM) cell having a current-controlling device and a RRAM device connected together, the method being free of a “forming” step and comprising setting the RRAM device to one of resistance levels by controlling the current-controlling device to one of current levels, wherein the setting the RRAM device includes applying a first voltage to a top electrode of the RRAM device and applying a second voltage to a bottom electrode of the RRAM device, the second voltage being higher than the first voltage.