Welcome to CQL Active Record! This guide will help you set up CQL in your Crystal project, connect to a database, define your first model, and perform basic CRUD, and first query. Use idiomatic Crystal and CQL, and provide clear, step-by-step examples.
struct User
include CQL::ActiveRecord::Model(Int32)
db_context AcmeDB, :users
property id : Int32?
property name : String
property email : String
property active : Bool = false
property created_at : Time?
property updated_at : Time?
end
4. Running Migrations
Create your tables using migrations (optional but recommended):
class CreateUsers < CQL::Migration
self.version = 1_i64
def up
schema.create :users do
primary_key :id, :serial
column :name, :string
column :email, :string
column :active, :bool, default: false
column :created_at, :timestamp
column :updated_at, :timestamp
end
end
def down
schema.drop :users
end
end
Run your migrations using your preferred migration runner.
5. Basic CRUD Operations
Create
user = User.new(name: "Alice", email: "alice@example.com")
user.save
Read
user = User.query.where(name: "Alice").first(User)
puts user.try(&.email)
Update
user = User.query.where(name: "Alice").first(User)
if user
user.active = true
user.save
end
Delete
user = User.query.where(name: "Alice").first(User)
user.try(&.delete)
6. Your First Query
# Find all active users
active_users = User.query.where(active: true).all(User)
active_users.each { |u| puts u.name }
