Re: Modeling Friendship Relationships

John R Pierce wrote
> a difficulty of the single entry for joe<->bob  is that its hard to have
> a unique constraint across two fields.     you'd want to ensure that
> joe+bob is unique and that there's no bob+joe

Bill's solution:

 PRIMARY KEY (person1, person2),
 CHECK (person1 < person2)

seems to make this constraint fairly simple...am I missing something?

Usage need permitting how difficult would setting up materialized views to
maintain arrays of "friend_of" and "friends_are" and simply unnest those
arrays if record-oriented access to the contained ids is required?  More
basically how performant (generally) are ~200 element arrays?

David J.




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