Support database views in diesel print-schema

[lukesutton]

Problem Description

The diesel print-schema command doesn't output definitions for database views in Postgresql.

What are you trying to accomplish?

For more complex queries I would like to be able to create a view in the database and associate it with a Queryable struct. This would be especially useful, since Postgresql now has support for materialized views.

What is the expected output?

I would expect the diesel cli to output macro calls for views. If not by default then as an option.

What is the actual output?

All tables, but no views.

[sgrif]

Unfortunately, we can't really do this until we more generally separate "data sources" from "tables". The problem is that all tables in Diesel must have a primary key, and there's no way that we could infer that. Humans can just pick a random arbitrary column and call that the primary key (and many views actually do logically have one), but I don't want to do that in Diesel CLI

[lukesutton]

Totally fair! I imagined there was some constraint there. My approach at this point has been to synthesize a primary key for rows in views and manually add table! declarations for them, which is working pretty well.

[sgrif]

Yup, that's the work around. For the record, I closed this issue, because that specific feature is not something we can support. That said, I do want to support views in general, as a separate concept from table!/Table (basically just not having a primary key), and when we do that they will absolutely be inferred by diesel print-schema and infer_schema!