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by mythz 3971 days ago
> FirstOrDefault being passed 2 rows = non-determinism... There's also Single being passed 2 rows = crash. SingleOrDefault being passed >1 rows = crash.

Which is the point of the different API's, you get to pick the behavior you want. Don't want it to crash? pick `FirstOrDefault`. A formal API is better than manually codifying the elected behavior each time, making it tedious to infer the intent each time whilst being susceptible to human errors manually copy+pasting imperative code.
1 comments
batou 3971 days ago
The problem is that it's a complex trade off whichever way you turn. Knowing which trade off to make is difficult for many people as it requires knowing all of the assumptions and conditions that are before and after the call as well as how the expression will react under all conditions. Add complex predicates to that,which the language encourages and it's pain.
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wvenable 3970 days ago
Except your example isn't a complex trade off -- it's just how it works. FirstOrDefault() returns the first or a default. It's right in the name? Which is first? Well you better provide an order if you care. If you don't care, don't provide an order. There is nothing complex about that at all.

It almost seems like your looking to blame Linq for what is clearly poor database and project design. If you have poor design you're going to have problems no matter what.

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