Manager API: orderBy expression

[Romain-Guillot]

With the Core API, we can use expressions in the orderBy clauses:

final query = select(db.todos) //
    ..orderBy([(t) => OrderingTerm.asc(t.name.lower())]);

Is there any plan to support expressions with the Manager API (beyond basic "column expressions")? For example:

database.managers.todos //
    ..orderBy((t) => t.name.lower().asc())

Or is there currently an official way to use expressions with the Manager API? For now, we can write something like that:

database.managers.todos //
    .orderBy((t) => ColumnOrderings(database.todos.name.lower()).asc())

But I don't think it's philosophically OK with the Manager API (to use the table directly without using the provided OrderingComposer). I didn't tested but as It will create an OrderingTerm with the provided expression, I think It works, but it feels wrong ;). And I don't know if we suppose to use the ColumnOrderings class as it is not documented in the official doc.

[dickermoshe]

The manager API was kept very simple, maybe too simple.

However, you can do what your describing using a computed field.

// First create an computed field with an expression you want to use
final lowerCaseName = db.managers.todos.computedField((o) => o.name.lower());
// Then use it
db.managers.todos.withFields([lowerCaseName]).orderBy((_) => lowerCaseName.orderings.asc())

[simolus3]

It will be hard to get the ..orderBy((t) => t.name.lower().asc()) syntax working without making asc() an extension on all Expressions (which is not terrible, but might also be confusing since we need an OrderingTerm in some places and a ComposableOrdering in others).

ColumnOrderings(database.todos.name.lower()).asc() is a bit dangerous if todos is in a joined/aliased position within the manager query. I think we could make something like orderBy((t) => t.name.computed((e) => e.lower()).asc() work, but... meh.
If we made the manager API just as expressive as the core query builder, I'm not convinced we'd end up with an easier API. So since this works with computed fields, I think leave things as-is.