[GlennS]

I would like to be able to explain the cost part better. It may just be personal bias of course.

1. There's no guarantee the correct theoretical model of your program fits the type system of your programming language.

2. Sometimes there are multiple correct models for different purposes in the same program, similar to how sometimes you need multiple views onto the same database tables.

3. Sometimes you just need the ability to bodge things.

[wtetzner]

> 2. Sometimes there are multiple correct models for different purposes in the same program, similar to how sometimes you need multiple views onto the same database tables.

Just wanted to point out that even though you can have multiple views or your database tables, they all still adhere to the same type system.

[GlennS]

I guess it's a problem that can be overcome with type inference then? (I don't have to declare types on queries, updates, or views, just on the base tables.)