Dami

A lightweight, policy-oriented ORM for Ruby on SQLite. One gem, no framework required.

Four-pillar DSL — structure (Dami.model), write rules (Dami.behavior), queries (Dami.scopes), presentation (Dami.present). Put something in the wrong block and Dami tells you where it goes.
Hardened writes by default — unknown fields raise, protected fields need an explicit permit:, every value is bound (never interpolated).
Real constraints — null:, unique:, default:, references: in migrations; foreign keys are enforced; violations come back as Dami::NotNullViolation, Dami::UniqueConstraintViolation, Dami::ForeignKeyViolation.
Flows — multi-step business operations that run in one transaction, roll back on failure, and fire side effects only after the commit.
Small and fast — a connection pool, WAL, prepared-statement cache, and nothing you didn't ask for.

Install

# Gemfile
gem "dami"

Five-minute tour

require "dami"

Dami.connect(:default, adapter: :sqlite, path: "app.db")

# Schema (or write a migration — see docs/09.Migrations.md)
Dami::Migration.new(Dami.database).create_table(:users) do |t|
  t.field :id, :primary_key
  t.field :email, :string, null: false, unique: true
  t.field :name, :string, null: false
  t.field :role, :string, default: "member"
  t.timestamps
end

# Structure
Dami.model :users do
  fields do
    field :email, :string
    field :name, :string
    field :role, :string
    field :created_at, :datetime
    field :updated_at, :datetime
  end
end

# Write-side rules
Dami.behavior :users do
  validate do
    rule :email, :required, :email
    rule :name, :required
  end
  protection { protect :role }
end

# Collection queries
Dami.scopes :users do
  scope :admins, -> { where(role: "admin") }
end

user = Dami.db(:users).create(email: "ana@example.com", name: "Ana")
user[:id]          # => 1
user.name          # => "Ana"
user[:created_at]  # => "2026-09-12 18:40:00" (UTC)

Dami.db(:users).where(id: user[:id]).update(name: "Ana G.")
Dami.db(:users).admins.count                 # => 0
Dami.db(:users).where(role: "admin").to_a    # => []

Dami.db(:users).create(email: "not-an-email", name: "")
# => Dami::ValidationError, errors: { email: ["must be valid email"], name: ["is required"] }

Dami.db(:users).where(id: 1).update(role: "admin")
# => Dami::ProtectionError (protected field) — pass permit: [:role] where you mean it

Documentation

Everything is in docs/, in reading order:

Scope

SQLite only, on purpose. If you need PostgreSQL or MySQL today, Dami is not the right tool yet.

Development

bundle install
rake test        # ruby test/run_all.rb
rake build       # gem build dami.gemspec

License

MIT — see LICENSE.

dami

Development

Runtime

Dami

Install

Five-minute tour

Documentation

Scope

Development

License