foundart
Transactions- what are the basics?
I have a situation similar to create and insert 2 associated models.
In my case User has_many Others and Others belongs_to User.
I want to insert a user and an Other in one transaction.
I’m doing a put_assoc from User and it works fine. It generates 2 insert statements of course.
My question is: Do I need to wrap the insert in a Repo.transaction? I have been unable to find any documentation that talks about how the inserts are handled. If I did not wrap the insert function in a transaction, would the 2 sql statements be batched in a single transaction by default or would they be done as 2 separate transactions?
MyModule.Repo.transaction fn ->
MyModule.Repo.insert(changeset)
end
Most Liked
szsoppa
If anyone coming to this topic needs more tips on Ecto.Multi and transactions in general, we’ve written a post about it: How database transactions work in Ecto and why Elixir makes it awesome? 
benwilson512
Yes, you can observe this with debug logging:
iex(5)> %Menu.Item{name: "Bar", price: 4.50, category: %Menu.Category{name: "Foo"}} |> Repo.insert!
[debug] QUERY OK db=0.3ms
begin []
[debug] QUERY OK db=6.6ms
INSERT INTO "categories" ("name","inserted_at","updated_at") VALUES ($1,$2,$3) RETURNING "id" ["Foo", {{2017, 11, 3}, {20, 21, 34, 814485}}, {{2017, 11, 3}, {20, 21, 34, 817077}}]
[debug] QUERY OK db=5.0ms
INSERT INTO "items" ("category_id","name","price","inserted_at","updated_at") VALUES ($1,$2,$3,$4,$5) RETURNING "id" [4, "Bar", #Decimal<4.5>, {{2017, 11, 3}, {20, 21, 34, 834005}}, {{2017, 11, 3}, {20, 21, 34, 834009}}]
[debug] QUERY OK db=0.8ms
commit []
Note the begin and commit lines. Those are the beginning and end of the transaction respectively.
theangryangel
You probably want an Ecto.Multi rather than using transactions directly as you get a bunch of extra stuff that you don’t get with Repo.transaction
Popular in Questions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Catch errors, track performance, monitor hosts and more.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #deployment
- #library
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #channels
- #elixirconf
- #exunit
- #discussion
- #code-sync
- #javascript
- #podcasts
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixir-ls
- #phoenix_html
- #iex
- #blog-post
- #graphql
- #genstage
- #ai
- #websockets
- #supervisor
- #advent-of-code
- #elixirconf-us
- #distillery
- #processes
- #forms
- #api
- #metaprogramming
- #security
- #performance
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Real-time error tracking, performance insights, and observability for devs.
Develop your skills with books, videos, and courses.
Producing high quality Elixir screencasts since 2017.
The deployment platform built for Elixir: PaaS ease, VPS control.
Courses that'll move you from confusion to "Aha, now I get it!"