Question

Hello stack overflow I need help with this problem.
Ok, I have a flat file database in php it records users , hobbies, fav movies and all.
Now i want to add a buddy system so they can have friends and send messages to each other in php without SQL.

Answer 1

Consider having another table (er, flat file?) that maintains links. “Mark” and “John” are buddies if there exists a row in this table (ff?) that links “Mark” and “John”. I’d recommend using some sort of index (you know, like a primary key).

Suppose you have a users table (or flat file, whatever, it doesn’t matter that much) that contains users and some data, it looks like this:

UID | Username | Hobbies
------------------------
1   | Mark     | Swimming, Sailing, Skiing
2   | John     | Biking, Paragliding
3   | Suzie    | Flying, Skiing

And you have this other friends table (again, flat file, whatever…):

Pair ID | A  | B
----------------
1       | 1  | 2
2       | 2  | 3

We’ve encoded in this friends table that Mark and John are friends, and that John and Suzie are friends, but with the absence of relation 1 and 3, we know that Mark and Suzie are not friends (at least according to our records).

Note that if you want to get all of John’s friends, you have to find all rows in your table (or file) that have John’s UID (here = 2) in either column A or column B.