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Elixir Ecto
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Quick Start

Quick Start

Learn essential Ecto operations and query patterns for effective database work with Elixir. This Quick Start teaches core Ecto concepts.

🎯 What You’ll Learn

By the end of this tutorial, you’ll understand:

  • Defining schemas and changesets
  • CRUD operations with Ecto
  • Querying with Ecto.Query
  • Associations and relationships

📋 Prerequisites

  • Ecto installed and configured (see Initial Setup)
  • Basic Elixir knowledge

📦 Defining Schemas

Create lib/myapp/user.ex:

defmodule MyApp.User do
  use Ecto.Schema
  import Ecto.Changeset

  schema "users" do
    field :name, :string
    field :email, :string
    field :age, :integer

    timestamps()
  end

  def changeset(user, attrs) do
    user
    |> cast(attrs, [:name, :email, :age])
    |> validate_required([:name, :email])
    |> validate_format(:email, ~r/@/)
    |> unique_constraint(:email)
  end
end

📊 CRUD Operations

Create 

alias MyApp.{Repo, User}

changeset = User.changeset(%User{}, %{name: "Alice", email: "alice@example.com", age: 30})
{:ok, user} = Repo.insert(changeset)

Read 

Repo.all(User)
Repo.get(User, 1)
Repo.get_by(User, email: "alice@example.com")

Update 

user = Repo.get!(User, 1)
changeset = User.changeset(user, %{age: 31})
{:ok, updated_user} = Repo.update(changeset)

Delete 

user = Repo.get!(User, 1)
{:ok, deleted_user} = Repo.delete(user)

🔍 Querying 

import Ecto.Query

# Basic queries
query = from u in User, select: u
Repo.all(query)

# Filtering
query = from u in User, where: u.age > 25, select: u
Repo.all(query)

# Ordering
query = from u in User, order_by: [desc: u.inserted_at], select: u
Repo.all(query)

# Limiting
query = from u in User, limit: 10, select: u
Repo.all(query)

🔗 Associations 

defmodule MyApp.Post do
  use Ecto.Schema

  schema "posts" do
    field :title, :string
    field :content, :text
    belongs_to :user, MyApp.User

    timestamps()
  end
end

# Query with preload
query = from u in User, preload: [:posts]
users = Repo.all(query)

✅ Next Steps

You now understand Ecto essentials! To deepen your knowledge:

  1. Try the examples: Execute each Ecto operation
  2. Explore By Example: Elixir Ecto By Example

🎯 Self-Assessment

After completing this Quick Start, you should be able to:

  • Define Ecto schemas
  • Perform CRUD operations
  • Write queries with Ecto.Query
  • Work with changesets and validations
  • Define associations between schemas
Last updated
Initial Setup