Diesel upsert experiment

Previous: https://github.com/pickfire/diesel-join-not-exist Next: https://github.com/pickfire/diesel-group-by

This time it requires diesel-git which isn't released.

Rust not able to recommend users::table when hello::schema::users is used even though it is a relative re-export.

on_conflict gets runtime error instead of compile-time error when non primary key or unique key is used. TODO

I was wondering how upsert could be done but is still surprised that all these could be made type-safe although there are a little bit of edge cases not being covered.

The example I tested out here have 3 struct (based on the previous ones). sqlite was used for easy testing.

+---------+     +---------+     +---------+
| User    |<-+  | Post    |     | Comment |
+---------+  |  +---------+     +---------+
| id      |  |  | id      |     | id      |
| name    |  |  | title   |     | body    |
|         |  |  | body    |<----+ post_id |
|         |  |  | user_id +--+--+ user_id |
+---------+  |  +---------+  |  +---------+
             +---------------+

I want to find all posts that does not have any comments. The query,

let query = diesel::insert_into(users)
    .values(&user)
    .on_conflict(id)
    .do_update()
    .set(name.eq(excluded(name)));

Which results in the SQL query,

INSERT INTO `users` (`id`, `name`)
VALUES (?, ?)
   ON CONFLICT (`id`)
   DO UPDATE SET `name` = excluded.`name` -- binds: [2, "John"]

Get started

Rust, diesel_cli (with sqlite feature) is required.

$ diesel migration run
$ cargo run --bin init  # populate database
$ cargo run --bin hello  # multi join query

pickfire/diesel-upsert

Diesel upsert experiment

Get started