How to build WHERE IN array clause with Ecto?
The following should work: posts = Post |> where([p], p.id in [1, 2]) |> Repo.all
elixir
What is a changeset in phoenix elixir
From the documentation: Changesets allow filtering, casting, validation and definition of constraints when manipulating models.. There is an example of working with changesets in the introductory documentation in the Ecto module. The functions change/2 and cast/4 are the usual entry points for creating changesets, while the remaining functions are useful for manipulating them. Changesets are … Read more
What is Elixir Plug?
Is it an abstraction layer between the two Yes, exactly! Plug is meant to be a generic adapter for different web servers. Currently we support just Cowboy but there is work to support others. Plug also defines how different components should be plugged together. Similar to Rack in Ruby, WSGI in Python, Ring in Clojure, … Read more
Encoding a Ecto Model to JSON in elixir
Update to Poison 1.5. With it you can declare in your models: @derive {Poison.Encoder, only: [:foo, :bar, :baz]} schema “your schema” do field :foo field :bar field :baz end It is going to be faster, safer and cleaner.
Data Types in Ecto – “value too long for type character varying(255)”
The error you get is from the underlying database where the column type is set to varchar which is what’s created by default when you specify the column type as string in a migration. To store a variable length string over 255 characters, you need to specify the column type as text in the migration. … Read more
Couldn’t find preset “es2015” relative to directory “web/static/js”
Please see the fix here: https://github.com/phoenixframework/phoenix/issues/1410 Upgrade to node >= v5.0.0 npm cache clean cd my_app rm -rf node_modules/ npm install mix phoenix.server
How do I load an Elixir library into iex without adding it to a project’s mix.exs deps?
Not a direct answer, but another way to maybe achieve what you want: You could have a playground project that you generate once (e.g. mix new playground) and that you can then relatively easily add new dependencies to. If you do iex -S mix within this project, you’ll get all its dependencies. If you want … Read more
Elixir: How to test multiple values in case condition?
There’s no direct syntax for or in the middle of patterns but you can use a guard: case testvalue do n when n in [200, 400] -> true _ -> false end You can also use or in guards. This will work too but is more verbose: case testvalue do n when n == 200 … Read more
Why is Elixir’s Access behaviour not a protocol?
As you’ve already mentioned, Access‘s implementation was changed to use Behaviours instead of Protocols. The reasoning was performance. Protocols are type/data based polymorphism, and are exclusive to Elixir. That means it lets you dispatch based on the data structure Behaviours are a typeless mechanism that don’t rely on a data structure, but the module as … Read more
What is =~ operator in elixir
It’s not documented on that page, but it’s documented in Kernel.=~/2 that when the RHS is a string, =~ checks if LHS contains RHS: iex(1)> “foo” =~ “f” true iex(2)> “foo” =~ “o” true It does not implicitly convert RHS to regex: iex(3)> “foo” =~ “.” false If RHS is a regular expression, returns true … Read more