ROD stands for Resident/Occupant Database. Your ROD includes everyone that you send your appeal to. Not everyone in your ROD will actually be a donor.
RODs contain common address information as well as more detailed postal routing data. RODs tend to be used as baselines for saturation mailouts. A ROD may be purchased from a commercial postal mailing list provider like ADVO. Most agencies that use KEYclick start off with an off-the-shelf ROD, then tweak it with name changes, deletions, and additions that they collect from their respondents.
RODs contain no information about actual donations that have been made. That information belongs in the Donation Database.
A set of records describing actual donations. For each donation, the donation database holds the donation amount, a link to the party making the donation, the date the donation was made, etc.
A donation database does not hold information about parties you've targeted but who have not made donations. That information belongs in a ROD.