MongoDB中许多具有相同字段或一个数组的文档

Question

Let's say I have a system where users can vote for items that come with an identificator.

Should I have a document for every user with an array of votes they had put in:

{user: A, votes: [x, y, z]}
{user: B, votes: [y, z]}
{user: C, votes: [x, z]}

or rather many documents for each vote:

{user: A, vote: x}, {user: A, vote: y}, {user: A, vote: z}
{user: B, vote: y}, {user: B, vote: z},
{user: C, vote: x}, {user: C, vote: z}

I feel like the second design is better but I might be wrong since I've only had experience with MySQL before.

Answer 1

According to me first design is better than that of second . Because you keep a document for a particular user . But in second case you are creating multiple document for a same user . Or you can create a document for particular votes ie who all are voted for x or y .... . Like

   {votes: X, users: [A,C]}
   {votes: Y, users: [A, B]}
   {votes: Z, users: [A, B,C]}