Postgres ON CONFLICT DO NOTHING

[Boscop]

How can I do something like:

INSERT INTO tags (name) values ('foo'), ('bar'), ('baz') ON CONFLICT DO NOTHING;

with diesel with postgres as backend.
Basically I want to insert all except the ones that are already in the table.
Without ON CONFLICT DO NOTHING it would unroll and not insert any if one is already in the table.

[killercup]

@sgrif worked on supporting UPSERT in November (ON CONFLICT DO UPDATE), which turned out to be pretty tricky.

Do you expect to get a return value with all the skipped rows?

[Boscop]

Not necessary. I just want to make sure that all tags are in the table after the query.
So I can get all their ids with the next query.

[sgrif]

Duplicate of #196

[emk]

We just ran into a case where we need this for our production application using a mix of diesel's PostgreSQL backend and some postgres. I'm probably going to have to roll back the diesel conversion of several tables that I just did. :-/

How much work would it be for me to implement this?

[Eijebong]

@emk If you really need this, you can use custom psql functions with sql_function!