Hi, my site allows donators (members) to make donations to charity competitions. The donators can also vote in a poll for each charity competition.

When a user makes a donation to a charity competition, they also have the right to submit one vote.

QUESTION
I want to change the system, so that the donators can make as many donations as they like to a charity competition but still only have one vote.

My current database looks like this:

id
charity_comp_id
member_id
donation_amount
vote_status (submitted / not submitted)
vote_answer

How should i setting this up so that users can submit as many donation as they like per competition but they are still only limited to one vote? Thanks in advance for your help...