NYCPHP Meetup

[Brian O'Connor]

I did this a few years ago and I believe I went with option 1 (disclaimer:
most what I did back then would be shunned by even the most beginner of
programmers).

#2 definitely has its advantages but goes against database normalization
theory (in my opinion), especially since there is inherently no "direction"
to friendship.

#1 can easily be sorted out using a few lines of php but is definitely
uglier.

Of course, if you really wanted to go table-happy you could make even the
notion of friendship based on joins :)
On Thu, Jul 30, 2009 at 4:02 PM, Allen Shaw <ashaw at polymerdb.org> wrote:

> Hi Gang,
>
> To support "friend" relationships in a contacts management database, I'm
> expecting to use a simple table like this one (plus a few columns for unique
> id, etc.):
>
> CREATE TABLE `tcontactrelationships` (
>  `contact1` int(11),
>  `contact2` int(11)
> );
>
> My concern is that when I'm looking for friends of contact #100, I'll have
> to search for '100' in both columns, because there's no reason that the
> value should be in only one column or the other. For example:
>
> +-----------+-----------+
> | contact1 | contact2 |
> +-----------+-----------+
> |      100    |      200   |
> |      300    |      100   |
> +-----------+-----------+
>
> Alternatively, I could create two rows for each relationship, so that I can
> always search only one column to find all relationships, e.g.,
>
> +-----------+-----------+
> | contact1 | contact2 |
> +-----------+-----------+
> |      100    |      200   |
> |      200    |      100   |
> |      300    |      100   |
> |      100    |      300   |
> +-----------+-----------+
>
> The second method seems better, smoother, less complicated when it comes
> time to pull out data from this table with joins to multiple other tables.
>  Of course I should only be adding/removing relationships within a
> transaction.  Can anyone suggest drawbacks or caveats I may be missing, or
> maybe suggest a better way?
>
> Thanks,
> Allen
>
> --
> Allen Shaw
> slidePresenter (http://slides.sourceforge.net)
>
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-- 
Brian O'Connor
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