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Comment by EarthLaunch | Hacker News Reader

An intriguing idea! I like this approach for being an innovative interface to SQL. I wonder if it would reduce cognitive load when interfacing with the DB.

I'm a game dev and often need to avoid situations where I'm using '.map' to iterate an entire array, for performance reasons. It would feel odd to use the concept, knowing it wasn't really iterating and/or was using an index. Is that how it works?

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It’s exactly what Entity Framework does in dotnet. It allows you to query the database like it’s an enumerable.

In fact, in EF, an IQueryable (which is the interface you use to query a SQL dataset) implements IEnumerable. So you can 100% manipulate your dataset like a normal array/list.

Sure it comes with its own shenanigans but 90% of the time it’s easy to read and to manipulate.

Performing a query with EF is able to do stuff that can't be done with `IEnumerable`. So that a filter()/.Where() can actually generate a WHERE clause instead of looping over every record.

Yes of course it generates the corresponding SQL and don’t iterate over the table.

But in the framework’s code, IQueryable implements IEnumerable, it’s just a totally different implementation but for the developer it’s 100% the same API and so any IQueryable can be used where a IEnumerable is expected.

This is a hazard that trips people up commonly. If you use an IQueryable where an IEnumerable is expected, it will use brute-force iteration semantics, and not do things like generating a WHERE clause. Linq provides similar extension methods for both interfaces, but you need to be sure your call resolves to the right interface, otherwise you'll end up doing things like pulling the whole table into memory.

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