I want to make a friends list in my online game. I am not sure how to set it up or where to start. The add friends and accept friends part I can handle, but I don\'t know how to
Check out the answers in this other post here on stackoverflow...some simple but great explanations to accomplishing what you need.
Facebook database design?
A friendship is essentially a mutual relationship between two people. In database terms it's a many-to-many relationship between two users.
So what you need is a linking table that holds references to two users by ID.
Users table
ID Username
1 Bob
2 Jim
3 Alice
Friends table
user1 user2
1 2
2 3
This would make Bob friends Jim and Jim friends with Alice.
An alternative would be to set column A as follow: $checkfriend = (($friend1 $friend2) || ($friend2 $friend1))
Column B as follow: (friendship accepted or friendship rejected) based on user's choice
Basically have both user1 and user2 in the same column.
If your friendship relationship is symmetrical, you can either store each pair in a separate record:
friend1 friend2
A B
B A
A C
B D
C B
D B
and query all B
's friends like that:
SELECT friend2
FROM friends
WHERE friend1 = 'B'
or store the user with the least id
in the first field and that with the greatest id
in the second one:
friend1 friend2
A B
A C
B D
and query B
's friends like that:
SELECT friend1
FROM friends
WHERE friend2 = 'B'
UNION ALL
SELECT friend2
FROM friends
WHERE friend1 = 'B'
The first option is a little bit more efficient in MySQL
, and this is the only option if your friendship relationship is not symmetrical (like on LiveJournal
)
See this article: