Re: Modeling Friendship Relationships

Thanks Jonathan. So in your use case would you put non-approved friend
requests in this table as non-reciprocal? If so, did the person requesting
friendship get the row in there or the person receiving the friend request?
Also, if A and B are friends, and B decided to remove A as a friend, are
you saying that you would not remove both rows?

Thanks!

On Thu, Nov 13, 2014 at 8:10 AM, Jonathan Vanasco <postgres(at)2xlp(dot)com> wrote:

>
> On Nov 11, 2014, at 5:38 PM, Robert DiFalco wrote:
>
> > Thoughts? Do I just choose one or is there a clear winner? TIA!
>
>
> I prefer this model
>
> user_id__a INT NOT NULL REFERENCES user(id),
> user_id__b INT NOT NULL REFERENCES user(id),
> is_reciprocal BOOLEAN
> primary key (user_id__a, user_id__b)
>
> if a relationship is confirmed (or dropped) I toggle is_reciprocal.
> having that value saves a lot of work doing joins or analyzing friendship
> sets
>
> if you have multiple relationship types, then things get tricky.
>
> you can either
> - treat the row as a triplet ( user_id__a, user_id__b,
> relationship_type_id) [i still recommend the reciprocal bool]
> - if you have a finite set of relationship types, you could just
> use each one as a bool column within the a2b row
>
> I've tried doing the "one row per relationship" approach, and didn't like
> it. the time savings on simple searches were marginally faster, but the
> sql was increasingly more complex and slower to execute as we leveraged the
> table into other queries.
>
>
>
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