module PgORM

Overview

PgORM - A type-safe, high-performance PostgreSQL ORM for Crystal.

PgORM provides an ActiveRecord-style interface for working with PostgreSQL databases, with compile-time type safety and zero-cost abstractions.

Features

Type-safe queries: All queries are type-checked at compile time
ActiveRecord-style API: Familiar interface for Rails developers
High performance: Zero runtime overhead, connection pooling, lazy loading
Full-text search: Native PostgreSQL FTS support with ranking
Real-time changefeeds: Subscribe to database changes via LISTEN/NOTIFY
Advisory locks: Distributed locking for critical sections
Pagination: Both offset-based and cursor-based pagination
Associations: belongs_to, has_one, has_many with autosave and dependent options
Validations: Built-in and custom validators
Callbacks: Lifecycle hooks for create, update, destroy
Transactions: Nested transaction support with savepoints

Quick Start

require "pg-orm"

# Configure database
PgORM::Database.configure do |settings|
  settings.host = "localhost"
  settings.db = "myapp"
  settings.user = "postgres"
end

# Define a model
class User < PgORM::Base
  include PgORM::Timestamps

  attribute id : Int64
  attribute name : String
  attribute email : String
  attribute active : Bool = true
end

# Create records
user = User.create!(name: "John", email: "[email protected]")

# Query records
users = User.where(active: true).order(:name).limit(10).to_a

# Update records
user.update!(name: "Jane")

# Delete records
user.destroy

Associations

class Author < PgORM::Base
  attribute id : Int64
  attribute name : String
  has_many :books
end

class Book < PgORM::Base
  attribute id : Int64
  attribute author_id : Int64
  attribute title : String
  belongs_to :author
end

author = Author.find(1)
author.books.each { |book| puts book.title }

Full-Text Search

# Simple search
Article.search("crystal programming", :title, :content)

# Weighted search (title more important)
Article.search_weighted("crystal", {
  title:   FullTextSearch::Weight::A,
  content: FullTextSearch::Weight::B,
})

# Ranked search (ordered by relevance)
Article.search_ranked("crystal", :title, :content)

Pagination

# Offset-based pagination
result = User.paginate(page: 2, limit: 20)
result.records.each { |user| puts user.name }
puts "Page #{result.page} of #{result.total_pages}"

# Cursor-based pagination (more efficient)
result = User.order(:id).paginate_cursor(limit: 20)
next_result = User.order(:id).paginate_cursor(after: result.next_cursor, limit: 20)

Changefeeds (Real-time Updates)

# Subscribe to changes
User.changes.on do |change|
  case change.event
  when .created?
    puts "New user: #{change.value.name}"
  when .updated?
    puts "Updated user: #{change.value.name}"
  when .deleted?
    puts "Deleted user: #{change.value.id}"
  end
end

Defined in:

pg-orm.cr
pg-orm/associations.cr
pg-orm/base.cr
pg-orm/changefeed.cr
pg-orm/collection.cr
pg-orm/errors.cr
pg-orm/full_text_search.cr
pg-orm/lock.cr
pg-orm/pagination.cr
pg-orm/persistence.cr
pg-orm/pg-adapter.cr
pg-orm/query.cr
pg-orm/query/builder.cr
pg-orm/query/cache.cr
pg-orm/query/iterator.cr
pg-orm/query/methods.cr
pg-orm/relation.cr
pg-orm/settings.cr

Constant Summary

VERSION = {{ (`shards version \"/srv/crystaldoc.info/github-spider-gazelle-pg-orm-v2.1.0/src\"`).chomp.stringify.downcase }}

CrystalDoc.info

pg-orm