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0 pointsToo10mo ago0 comments

With an ORM your application code is your views.

You can write reusable plain functions as abstractions, returning QuerySets that allow further filters being chained onto the query, before the actual SQL is materialized and sent to the database.

The result of this doesn’t have to match the original object models you defined, it’s still possible to be flexible with group bys resulting in dictionaries.

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4 comments · 2 top-level

tremon10mo ago· 1 in thread

But converting a SQL relation to a set of dictionaries already carries a lot of overhead: every cell in the resultset must be converted to a key-value pair. And the normal mechanics of vertical "slicing" a set of dictionaries is much more expensive than doing the same in a 2d relation array. So while you might want to offer a dictionary-like interface for the result set, please don't use a dictionary-like data structure.

zbentley10mo ago

There are valid reasons to avoid complex ORM/query result representations, but this isn’t one of them.

I have very rarely seen or even heard of the result representation data structure for an SQL query being a bottleneck. The additional time and space needed to represent a raw tabular result in a more useful way on the client are nearly always rounding errors compared by the time needed to RPC the query itself and the space taken up by the raw bytes returned. Given that, and the engineering time wasted working with (and fixing inevitable bugs in) fully tabular result data structures (arrays, bytes), this is bad advice.

henry202310mo ago· 1 in thread

Unpopular opinion. ORM by definition is the gcd of "supported databases" features. It exists only because people doesn't like the aesthetics of SQL but the cost to use them is immense.

CuriouslyC10mo ago

Not unpopular. ORM hate is real. I like SQL Alchemy and Drizzle in projects for the features they give you for free (such as Alembic migrations and instant GraphQL server), but I still write SQL for most stuff.

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