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Rename phoenix-ecto@1.3 to phoenix-ecto
This commit is contained in:
Rico Sta. Cruz
parent
0d4e4095ed
commit
472f6b3ae6
209
phoenix-ecto.md
209
phoenix-ecto.md
@ -1,5 +1,210 @@
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---
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title: "Phoenix: Ecto models"
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title: "Phoenix: Ecto"
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category: Elixir
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redirect_to: /phoenix-ecto@1.3
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layout: 2017/sheet
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tags: [WIP]
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updated: 201708.29
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---
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## Schemas
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{: .-three-column}
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### Generating
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```bash
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$ mix phx.gen.html \
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Accounts \ # domain
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Profile \ # schema
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profiles \ # table name
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email:string \
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age:integer
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```
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### Schema
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```elixir
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defmodule Myapp.Accounts.User do
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use Ecto.Schema
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schema "users" do
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field :name
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field :age, :integer
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field :password, virtual: true
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timestamps()
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end
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end
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```
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### Field types
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| Field |
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| --- |
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| `:id` |
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| `:binary` |
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| `:boolean` |
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| `:string` |
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| --- |
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| `:integer` |
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| `:float` |
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| `:decimal` |
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| --- |
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| `{:array, inner_type}` |
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| `:map` |
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{: .-left-align}
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## Changesets
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### Changesets
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```elixir
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def changeset(user, params \\ :empty) do
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%User{}
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|> Ecto.Changeset.change # basic casting to changeset
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user
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|> cast(params, ~w(name email), ~w(age)) # params to Changeset
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|> validate_format(:email, ~r/@/)
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|> validate_inclusion(:age, 18..100)
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|> validate_exclusion(:role, ~w(admin superadmin))
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|> validate_subset(:pets, ~w(cat dog parrot whale))
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|> validate_length(:body, min: 1)
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|> validate_length(:body, min: 1, max: 160)
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|> validate_length(:partners, is: 2)
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|> validate_number(:pi, greater_than: 3)
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|> validate_number(:pi, less_than: 4)
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|> validate_number(:pi, equal_to: 42)
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|> validate_change(:title, fn _, _ -> [])
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|> validate_confirmation(:password, message: "does not match")
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|> unique_constraint(:email)
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|> foreign_key_constraint(:post_id)
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|> assoc_constraint(:post) # ensure post_id exists
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|> no_assoc_constraint(:post) # negative (useful for deletions)
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end
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```
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### Changeset fields
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```elixir
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changeset.valid?
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changeset.errors #=> [title: "empty"]
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changeset.changes #=> %{}
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changeset.params[:title]
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changeset.required #=> [:title]
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changeset.optional #=> [:body]
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```
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### Updating
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```elixir
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changeset #(or model)
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|> change(title: "New title")
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|> change(%{ title: "New title" })
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|> put_change(:title, "New title")
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|> force_change(:title, "New title")
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|> update_change(:title, &(&1 <> "..."))
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|> delete_change(:title)
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|> merge(other_changeset)
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|> add_error(:title, "empty")
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```
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### Getting
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```elixir
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get_change(changeset, :title) #=> "hi" (if changed)
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get_field(changeset, :title) #=> "hi" (even if unchanged)
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fetch_change(changeset, :title) #=> {:ok, "hi"} | :error
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fetch_field(changeset, :title) #=> {:changes | :model, "value"} | :error
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```
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## Repo
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### Get one
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```elixir
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Repo.get(User, id)
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Repo.get_by(User, email: "john@hello.com") #=> %User{} | nil
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# also get! get_by!
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```
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### Create/update
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```elixir
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changeset |> Repo.update
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changeset |> Repo.insert
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changeset |> Repo.insert_or_update
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```
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```
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User
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|> Ecto.Changeset.change(%{name: "hi"})
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|> Repo.insert
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```
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## Many
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### Queries
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```elixir
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from p in Post,
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where: p.title == "Hello",
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where: [state: "Sweden"],
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limit: 1,
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offset: 10,
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order_by: c.name,
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order_by: [c.name, c.title],
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order_by: [asc: c.name, desc: c.title],
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preload: [:comments],
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preload: [comments: {c, likes: l}],
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join: c in assoc(c, :comments),
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join: p in Post, on: c.post_id == p.id,
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group_by: p,
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select: p,
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select: {p.title, p.description},
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select: [p.title, p.description],
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```
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### Get many
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```elixir
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Repo.all(User)
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```
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### Update many
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```elixir
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Repo.update_all(Post, set: [title: "Title"])
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Repo.update_all(Post, inc: [views: 1])
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```
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### Chaining `_all` with queries
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```elixir
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from(p in Post, where: p.id < 10)
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|> Repo.update_all(...)
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from(p in Post, where: p.id < 10)
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|> Repo.all()
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```
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## References
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{: .-one-column}
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- Based on Ecto 1.3.
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@ -1,205 +1,5 @@
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---
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title: "Phoenix: Ecto"
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title: "Phoenix: Ecto models"
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category: Elixir
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layout: 2017/sheet
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tags: [WIP]
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updated: 201708.29
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redirect_to: /phoenix-ecto
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---
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## Schemas
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{: .-three-column}
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### Generating
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```bash
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$ mix phx.gen.html \
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Accounts \ # domain
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Profile \ # schema
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profiles \ # table name
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email:string \
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age:integer
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```
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### Schema
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```elixir
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defmodule Myapp.Accounts.User do
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use Ecto.Schema
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schema "users" do
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field :name
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field :age, :integer
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field :password, virtual: true
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timestamps()
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end
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end
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```
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### Field types
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| Field |
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| --- |
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| `:id` |
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| `:binary` |
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| `:boolean` |
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| `:string` |
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| --- |
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| `:integer` |
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| `:float` |
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| `:decimal` |
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| --- |
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| `{:array, inner_type}` |
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| `:map` |
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{: .-left-align}
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## Changesets
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### Changesets
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```elixir
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def changeset(user, params \\ :empty) do
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%User{}
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|> Ecto.Changeset.change # basic casting to changeset
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user
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|> cast(params, ~w(name email), ~w(age)) # params to Changeset
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|> validate_format(:email, ~r/@/)
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|> validate_inclusion(:age, 18..100)
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|> validate_exclusion(:role, ~w(admin superadmin))
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|> validate_subset(:pets, ~w(cat dog parrot whale))
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|> validate_length(:body, min: 1)
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|> validate_length(:body, min: 1, max: 160)
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|> validate_length(:partners, is: 2)
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|> validate_number(:pi, greater_than: 3)
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|> validate_number(:pi, less_than: 4)
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|> validate_number(:pi, equal_to: 42)
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|> validate_change(:title, fn _, _ -> [])
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|> validate_confirmation(:password, message: "does not match")
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|> unique_constraint(:email)
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|> foreign_key_constraint(:post_id)
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|> assoc_constraint(:post) # ensure post_id exists
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|> no_assoc_constraint(:post) # negative (useful for deletions)
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end
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```
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### Changeset fields
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```elixir
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changeset.valid?
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changeset.errors #=> [title: "empty"]
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changeset.changes #=> %{}
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changeset.params[:title]
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changeset.required #=> [:title]
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changeset.optional #=> [:body]
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```
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### Updating
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```elixir
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changeset #(or model)
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|> change(title: "New title")
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|> change(%{ title: "New title" })
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|> put_change(:title, "New title")
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|> force_change(:title, "New title")
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|> update_change(:title, &(&1 <> "..."))
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|> delete_change(:title)
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|> merge(other_changeset)
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|> add_error(:title, "empty")
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```
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### Getting
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```elixir
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get_change(changeset, :title) #=> "hi" (if changed)
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get_field(changeset, :title) #=> "hi" (even if unchanged)
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fetch_change(changeset, :title) #=> {:ok, "hi"} | :error
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fetch_field(changeset, :title) #=> {:changes | :model, "value"} | :error
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```
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## Repo
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### Get one
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```elixir
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Repo.get(User, id)
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Repo.get_by(User, email: "john@hello.com") #=> %User{} | nil
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# also get! get_by!
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```
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### Create/update
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```elixir
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changeset |> Repo.update
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changeset |> Repo.insert
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changeset |> Repo.insert_or_update
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```
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```
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User
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|> Ecto.Changeset.change(%{name: "hi"})
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|> Repo.insert
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```
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## Many
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### Queries
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```elixir
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from p in Post,
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where: p.title == "Hello",
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where: [state: "Sweden"],
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limit: 1,
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offset: 10,
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order_by: c.name,
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order_by: [c.name, c.title],
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order_by: [asc: c.name, desc: c.title],
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preload: [:comments],
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preload: [comments: {c, likes: l}],
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join: c in assoc(c, :comments),
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join: p in Post, on: c.post_id == p.id,
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group_by: p,
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select: p,
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select: {p.title, p.description},
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select: [p.title, p.description],
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```
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### Get many
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```elixir
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Repo.all(User)
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```
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### Update many
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```elixir
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Repo.update_all(Post, set: [title: "Title"])
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Repo.update_all(Post, inc: [views: 1])
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```
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### Chaining `_all` with queries
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```elixir
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from(p in Post, where: p.id < 10)
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|> Repo.update_all(...)
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from(p in Post, where: p.id < 10)
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|> Repo.all()
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```
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