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by pat_shaughnessy 4260 days ago
Oh absolutely. I thought about saying that, and just ran out of energy before posting the article this morning.

The reason I used this particular SQL statement as an example is that ActiveRecord (a Ruby ORM) generates it from a fairly simple, common Ruby expression. I suppose ActiveRecord could be improved to drop the sort when you know there's one one possible match.
1 comments
talaketu 4260 days ago
Unless "name" is unique, there could be multiple matches. Asking for the "first" demands an ordering.

Perhaps (a) the user doesn't care what ordering is used, and/or (b) (such as in your example in the preceding post) hasn't specified an order (and apparently PK ordering is defaulted to PK - a model option?). It would be error-prone for ORM to take (b) as implying (a).

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pat_shaughnessy 4260 days ago
Yes, good point. Rails has a lot of conventions like this - that "first" implies ordering by primary key (by default). I just imagine that most Rails developers don't think about sorting and its implications when they ask for the first record.
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