Let's consider a more complicated scenario: the connection between users and photos.
A user can post many photos. But a photo can also be connected to many users.
Putting a single foreign key in one of those tables won't suffice. Instead, we must first ponder the real-world word we use to describe the connection between a photo and a user.
How about appearance?
| id | name | location |
|---|---|---|
| 45 | Cookie Monster | New York |
| 46 | Kermit The Frog | Los Angeles |
| 47 | Fozzie Bear | Austin |
| id | image_data |
|---|---|
| 802 | 45A76C98A12... |
| 803 | 91B1EF719B8... |
| id | user_id | photo_id |
|---|---|---|
| 73 | 45 | 802 |
| 74 | 46 | 802 |
| 75 | 47 | 802 |
| 76 | 46 | 803 |