Examples for axiom-memory-adapter

axiom-memory-adapter-examples.rb

require 'axiom-memory-adapter'

adapter = Axiom::Adapter::Memory.new

# setup base relations
adapter['customers'] = Axiom::Relation::Empty.new(
  [[:id, Integer], [:name, String]]
)

adapter['orders'] = Axiom::Relation::Empty.new(
  [[:id, Integer], [:customer_id, Integer]]
)

# insert customer data
customers = adapter['customers']
customers.insert([[1, 'Dan Kubb']])
customers.insert([[2, 'John Doe']])

# insert order data
orders = adapter['orders']
orders.insert([[1, 1]])
orders.insert([[2, 1]])
orders.insert([[3, 1]])
orders.insert([[4, 2]])

# join customers and orders
customer_orders = customers.
  rename(id: :customer_id).
  join(orders.rename(id: :order_id))

# demonstrate writable view-like behaviour

# insert into the join
customer_orders.insert([[3, 'Jane Doe', 5]])

# inserts are propagated to the base relations
adapter['customers'].count  # => 3
adapter['orders'].count     # => 5

# delete from a join
customer_orders.delete([[3, 'Jane Doe', 5]])

# deletes are propagated to the base relations
adapter['customers'].count  # => 2
adapter['orders'].count     # => 4