ecto

You have to use modify/3 to change the type. add/3 is only for adding new columns. alter table(:editables) do modify :content, :binary end

This is an old question and the previously accepted answer was no longer the de facto way. Ecto now supports HABTM or many to many associations. https://hexdocs.pm/ecto/Ecto.Schema.html#many_to_many/3 many_to_many :users, MyApp.User, join_through: “chat_group_users”

The options that Dogbert has provided are both correct and should be used for Ecto 1.x. In Ecto 2.0 you can use Repo.aggregate/4 Repo.aggregate(Post, :count, :id)

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

I’m not sure when this was added to Ecto, but at least in 2.1.6 there’s no need for raw SQL anymore. drop/1 now supports constraints (drop_if_exists/1 doesn’t though): def up do drop constraint(:videos, “videos_user_id_fkey”) alter table(:videos) do modify :user_id, references(:users, on_delete: :delete_all) end end def down do drop constraint(:videos, “videos_user_id_fkey”) alter table(:videos) do modify :user_id, … Read more

The following should work: posts = Post |> where([p], p.id in [1, 2]) |> Repo.all

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

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.