Proposal: multi_create method for bulk records

[davydovanton]

Now we can use #create method for this. But I think it will be better to create the different method for this. We should use #command here. If you don't mind, I can create PR for this 👍

How we can use in in projects:

repo = BookRepository.new
books = repo.multi_create([{ title: 'Hanami' }, { title: 'Ruby' }])
books # => array of entity 

[jodosha]

I'm not for expanding repository public API to bulk operations, because it's a gateway for "find", "update", "delete" in bulk feature requests.

As they aren't common use case, developers can implement by their own, and/or use upcoming Hanami::Model::Command /cc @hlegius

[jodosha]

@davydovanton PS Please use the forum for proposals and please leave GH issues for actionable tickets that we have already agreed on. Thank you very much. 💚

[spectator]

As they aren't common use case, developers can implement by their own, and/or use upcoming Hanami::Model::Command

@jodosha would you point me to a direction how something like multi_create can be implemented w/o upcoming Hanami::Model::Command ?

[mereghost]

@spectator You can plug directly on rom commands, be aware that the following line won't update your created_at and updated_at fields

class SomeRepository < Hanami::Repository
  def bulk_insert(data)
    command(:create, somes, result: :many).call(data)
  end
end

[spectator]

Thanks a lot @mereghost ! I led myself too deep into ROM commands and completely overlooked something as simple as this. BTW, you can add timestamps plugin like so

class SomeRepository < Hanami::Repository
  def bulk_insert(data)
    command(:create, somes, use: [:timestamps], result: :many).call(data)
  end
end

[solnic]

rom-rb may use a bulk insert whenever you pass in a collection of tuples (or structs, doesn't matter). It of course depends on the db backend, so ie on PG we use multi_insert which does a bulk insert on the database side. This is completely transparent from the user point of view because each adapter may provide custom command subclasses for each database type. It's also worth to mention that in rom-rb there's no concept of inserting a single tuple / struct, it always operates on collections of data, even when you pass in a single tuple it'll be put it into a single-element array and pass down to dataset backend, if its size is > 1 multi insert will be used.

...anyhow, what I'm trying to say is that there's absolutely no need for a special bulk insert API because rom-rb handles it for you, and if you don't like that it's implicit, you can always drop down to the relation API and call multi_insert yourself.

Here's what I'm talking about (using rom-4 from master):

[3] pry(main)> users = rom.relations[:users]
=> #<ROM::Relation[Users] name=ROM::Relation::Name(users) dataset=#<Sequel::Postgres::Dataset: "SELECT \"id\", \"name\" FROM \"users\" ORDER BY \"users\".\"id\"">>
[4] pry(main)> users.command(:create).call(name: "Jane")
I, [2017-06-25T16:36:49.128106 #23731]  INFO -- : (0.082191s) INSERT INTO "users" ("name") VALUES ('Jane') RETURNING *
=> {:id=>2, :name=>"Jane"}
[5] pry(main)> users.command(:create, result: :many).call([{name: "Jane"}, {name: "John"}])
I, [2017-06-25T16:37:15.031153 #23731]  INFO -- : (0.000187s) BEGIN
I, [2017-06-25T16:37:15.031634 #23731]  INFO -- : (0.000386s) INSERT INTO "users" ("name") VALUES ('Jane'), ('John') RETURNING *
I, [2017-06-25T16:37:15.032716 #23731]  INFO -- : (0.000964s) COMMIT
=> [{:id=>5, :name=>"Jane"}, {:id=>6, :name=>"John"}]

[spectator]

@solnic I see what you mean, but hanami-repository always returns one result even though collection of tuples was passed into create and rom-rb of course created all those records in the database, and thus the need for special bulk insert API so I can get full result back.